fix: sync MTProto startup and egress fixes

cmd/telesrv/main.go

@@ -347,11 +347,6 @@ func run(logger *zap.Logger) error {
 	defer func() { _ = rdb.Close() }()
 	logger.Info("持久化依赖就绪", zap.String("redis", cfg.RedisAddr))
 
-	ln, err := net.Listen("tcp", cfg.ListenAddr)
-	if err != nil {
-		return fmt.Errorf("listen %q: %w", cfg.ListenAddr, err)
-	}
-
 	authKeyStore := postgres.NewAuthKeyStore(pool)
 	userStore := postgres.NewUserStore(pool)
 	authzStore := postgres.NewAuthorizationStore(pool)
@@ -858,7 +853,7 @@ func run(logger *zap.Logger) error {
 		OutboundControlQueueSize:      cfg.MTProtoOutboundControlQueueSize,
 		OutboundTrackedGlobalMaxBytes: cfg.MTProtoOutboundTrackedGlobalMaxBytes,
 		OutboundWriteGlobalMaxBytes:   cfg.MTProtoOutboundWriteGlobalMaxBytes,
-	})
+		OnServing: func(_ net.Addr) {
 			logger.Info("telesrv 服务就绪",
 				zap.String("listen", cfg.ListenAddr),
 				zap.String("advertise", net.JoinHostPort(cfg.AdvertiseIP, portStr)),
@@ -867,5 +862,9 @@ func run(logger *zap.Logger) error {
 				zap.Uint("schema_version", migrationStatus.Version),
 				zap.String("blob_backend", "localfs"),
 			)
-	return srv.Serve(ctx, ln)
+		},
+	})
+	// This is intentionally the final startup operation. ListenAndServe owns the
+	// public listener so no seed/prewarm work can run after port 2398 is exposed.
+	return srv.ListenAndServe(ctx, cfg.ListenAddr)
 }

internal/mtprotoedge/conn.go

@@ -61,6 +61,10 @@ type Conn struct {
 
 	outbound        chan outboundOp
 	outboundControl chan outboundOp
+	// Critical RPC results (session/difference convergence) and large bulk
+	// responses have independent bounded lanes. The actor remains the sole writer.
+	outboundCritical chan outboundOp
+	outboundBulk     chan outboundOp
 	outboundStop     chan struct{}
 	outboundDone     chan struct{}
 	outboundClose    sync.Once
@@ -103,6 +107,12 @@ type Conn struct {
 	rpcRunning       int
 	rpcReady         bool
 	rpcClosed        bool
+	// Rewrap aliasing never delays execution. initialized stops collecting
+	// candidates after the first valid init wrapper on this physical generation.
+	rpcRewrapInitialized atomic.Bool
+	// rpcResultAcked is invoked by the sole outbound actor after it resolves an
+	// acknowledged server frame back to the rpc_result request msg_id.
+	rpcResultAcked func(*Conn, int64)
 	// inflightRPCBytes 跟踪已入队未完成的 inbound RPC body 总字节，配合 maxInflightRPCBytes
 	// 给 RPC 队列设字节预算（不止限条数），防对抗客户端发大请求撑内存。
 	inflightRPCBytes atomic.Int64

internal/mtprotoedge/connection_intake.go

@@ -0,0 +1,95 @@
+package mtprotoedge
+
+import (
+	"net"
+	"time"
+
+	"go.uber.org/zap"
+)
+
+type connectionIntakeEvent struct {
+	stage     string
+	outcome   string
+	transport string
+	remote    string
+	local     string
+	duration  time.Duration
+	bytes     int
+	err       error
+}
+
+func (s *Server) signalServing(addr net.Addr) {
+	if s.onServing != nil {
+		s.onServing(addr)
+	}
+}
+
+func (s *Server) observeConnectionIntake(event connectionIntakeEvent) {
+	fields := []zap.Field{
+		zap.String("phase", event.stage),
+		zap.String("outcome", event.outcome),
+	}
+	if event.transport != "" {
+		fields = append(fields, zap.String("transport", event.transport))
+	}
+	if event.remote != "" {
+		fields = append(fields, zap.String("remote_addr", event.remote))
+	}
+	if event.local != "" {
+		fields = append(fields, zap.String("local_addr", event.local))
+	}
+	if event.duration > 0 {
+		fields = append(fields, zap.Duration("duration", event.duration))
+	}
+	if event.bytes > 0 {
+		fields = append(fields, zap.Int("bytes", event.bytes))
+	}
+	if event.err != nil {
+		fields = append(fields, zap.Error(event.err))
+	}
+	s.log.Debug("Connection intake", fields...)
+	if metrics, ok := s.metrics.(ConnectionIntakeMetrics); ok {
+		metrics.ConnectionIntake(event.stage, event.outcome, event.duration)
+	}
+}
+
+func (s *Server) observeRawAccepts(ln net.Listener) net.Listener {
+	return &connectionObservedListener{Listener: ln, observe: s.observeConnectionIntake}
+}
+
+type connectionObservedListener struct {
+	net.Listener
+	observe func(connectionIntakeEvent)
+}
+
+func (l *connectionObservedListener) Accept() (net.Conn, error) {
+	conn, err := l.Listener.Accept()
+	if err != nil {
+		return nil, err
+	}
+	l.observe(connectionIntakeEvent{
+		stage: "raw_accept", outcome: "accepted", remote: connRemote(conn), local: connLocal(conn),
+	})
+	return conn, nil
+}
+
+func connRemote(conn net.Conn) string {
+	if conn == nil || conn.RemoteAddr() == nil {
+		return ""
+	}
+	return conn.RemoteAddr().String()
+}
+
+func connLocal(conn net.Conn) string {
+	if conn == nil || conn.LocalAddr() == nil {
+		return ""
+	}
+	return conn.LocalAddr().String()
+}
+
+func intakeTransport(obfuscated bool) string {
+	if obfuscated {
+		return "obfuscated_tcp"
+	}
+	return "tcp"
+}

internal/mtprotoedge/connection_intake_test.go

@@ -0,0 +1,170 @@
+package mtprotoedge
+
+import (
+	"context"
+	"net"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+)
+
+func TestListenAndServeCallsServingHookOnBoundListener(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	metrics := newIntakeCaptureMetrics()
+	hookEntered := make(chan net.Addr, 1)
+	releaseHook := make(chan struct{})
+	hookReleased := false
+	defer func() {
+		if !hookReleased {
+			close(releaseHook)
+		}
+	}()
+	srv := New(Options{Metrics: metrics, OnServing: func(addr net.Addr) {
+		hookEntered <- addr
+		<-releaseHook
+	}})
+	done := make(chan error, 1)
+	go func() { done <- srv.ListenAndServe(ctx, "127.0.0.1:0") }()
+
+	var addr net.Addr
+	select {
+	case addr = <-hookEntered:
+	case <-time.After(3 * time.Second):
+		t.Fatal("serving callback was not published")
+	}
+	conn, err := net.DialTimeout("tcp", addr.String(), time.Second)
+	if err != nil {
+		t.Fatalf("dial after serving callback: %v", err)
+	}
+	_ = conn.Close()
+
+	// The observation hook is still blocked: raw_accept can only advance here
+	// when the intake loop was installed before OnServing was called.
+	deadline := time.After(3 * time.Second)
+	for !hasIntakeEvent(metrics.snapshot(), "raw_accept", "accepted") {
+		select {
+		case <-metrics.wake:
+		case <-deadline:
+			t.Fatal("raw accept loop did not run while serving hook was blocked")
+		}
+	}
+	close(releaseHook)
+	hookReleased = true
+
+	cancel()
+	select {
+	case err := <-done:
+		if err != nil {
+			t.Fatalf("ListenAndServe shutdown: %v", err)
+		}
+	case <-time.After(3 * time.Second):
+		t.Fatal("ListenAndServe did not stop")
+	}
+}
+
+type intakeCaptureMetrics struct {
+	NopMetrics
+
+	mu     sync.Mutex
+	events []intakeMetricEvent
+	wake   chan struct{}
+}
+
+type intakeMetricEvent struct {
+	stage   string
+	outcome string
+}
+
+func newIntakeCaptureMetrics() *intakeCaptureMetrics {
+	return &intakeCaptureMetrics{wake: make(chan struct{}, 16)}
+}
+
+func (m *intakeCaptureMetrics) ConnectionIntake(stage, outcome string, _ time.Duration) {
+	m.mu.Lock()
+	m.events = append(m.events, intakeMetricEvent{stage: stage, outcome: outcome})
+	m.mu.Unlock()
+	select {
+	case m.wake <- struct{}{}:
+	default:
+	}
+}
+
+func (m *intakeCaptureMetrics) snapshot() []intakeMetricEvent {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	return append([]intakeMetricEvent(nil), m.events...)
+}
+
+func TestConnectionIntakeStagesIncludePrePromotionDisconnect(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	metrics := newIntakeCaptureMetrics()
+	ready := make(chan net.Addr, 1)
+	srv := New(Options{
+		Metrics:       metrics,
+		ObfuscatedTCP: true,
+		WebSocket:     true,
+		OnServing: func(addr net.Addr) {
+			ready <- addr
+		},
+	})
+	done := make(chan error, 1)
+	go func() { done <- srv.ListenAndServe(ctx, "127.0.0.1:0") }()
+
+	var addr net.Addr
+	select {
+	case addr = <-ready:
+	case <-time.After(3 * time.Second):
+		t.Fatal("serving callback was not published")
+	}
+	conn, err := net.DialTimeout("tcp", addr.String(), time.Second)
+	if err != nil {
+		t.Fatalf("dial: %v", err)
+	}
+	// Four non-HTTP bytes let the mux classify the connection as raw MTProto;
+	// closing before the remaining obfuscated2 header arrives must still expose
+	// the exact transport_promote failure phase.
+	if _, err := conn.Write([]byte{1, 2, 3, 4}); err != nil {
+		t.Fatalf("write prefix: %v", err)
+	}
+	_ = conn.Close()
+
+	deadline := time.After(3 * time.Second)
+	for {
+		events := metrics.snapshot()
+		if hasIntakeEvent(events, "raw_accept", "accepted") &&
+			hasIntakeEvent(events, "mux_sniff", "ready") &&
+			hasIntakeEvent(events, "transport_dispatch", "accepted") &&
+			hasIntakeEvent(events, "transport_promote", "client_disconnect") {
+			break
+		}
+		select {
+		case <-metrics.wake:
+		case <-deadline:
+			t.Fatalf("intake events did not converge: %v", events)
+		}
+	}
+
+	cancel()
+	select {
+	case err := <-done:
+		if err != nil && !strings.Contains(err.Error(), "closed") {
+			t.Fatalf("server shutdown: %v", err)
+		}
+	case <-time.After(3 * time.Second):
+		t.Fatal("server did not stop")
+	}
+}
+
+func hasIntakeEvent(events []intakeMetricEvent, stage, outcome string) bool {
+	for _, event := range events {
+		if event.stage == stage && event.outcome == outcome {
+			return true
+		}
+	}
+	return false
+}

internal/mtprotoedge/encrypted.go

@@ -260,6 +260,9 @@ func (s *Server) handleEncrypted(ctx context.Context, tc transport.Conn, cs *con
 	if err := s.executeInboundPlan(ctx, cs, current, plan); err != nil {
 		return current, err
 	}
+	if err := plan.commitRewrapAliases(s); err != nil {
+		return current, err
+	}
 	if err := plan.commitRPCBatch(); err != nil {
 		return current, err
 	}
@@ -268,12 +271,6 @@ func (s *Server) handleEncrypted(ctx context.Context, tc transport.Conn, cs *con
 			return current, err
 		}
 	}
-	// An overlapping cross-connection owner may run until RPCTimeout. ACK the
-	// accepted duplicate before joining it so the new client does not build a
-	// retransmit storm while its read loop waits for the shared result.
-	if err := s.executePendingRPCReplays(ctx, current, plan); err != nil {
-		return current, err
-	}
 	return current, nil
 }
 
@@ -577,58 +574,6 @@ func mergeStateInfo(primary, fallback []byte) []byte {
 	return info
 }
 
-// enqueueRPC 重试一个旧 owner 未发布结果的请求。正常收包统一走 container batch；
-// 这里也用长度为 1 的 batch，避免维护第二套预算/commit 状态机。
-func (s *Server) enqueueRPC(ctx context.Context, c *Conn, msgID int64, typeID uint32, request *bin.Buffer) error {
-	method := s.typeName(typeID)
-	claim, err := s.rpcResults.Acquire(c.authKeyID, c.sessionID, msgID)
-	if err != nil {
-		if errors.Is(err, ErrRPCResultFlightCapacity) {
-			c.metrics.InboundRPCDropped(method, "flight_capacity")
-			return s.handleInboundRPCAdmissionError(ctx, c, msgID, method, ErrInboundRPCQueueFull)
-		}
-		return err
-	}
-	switch claim.state {
-	case rpcResultAcquireCompleted:
-		s.log.Info("RPC duplicate replay from session cache",
-			zap.String("method", method),
-			zap.Int64("msg_id", msgID),
-			zap.String("auth_key_id", c.authKeyHex),
-			zap.Int64("session_id", c.sessionID),
-		)
-		return s.sendCachedRPCResult(ctx, c, claim.encoded)
-	case rpcResultAcquirePending:
-		encoded, ok, waitErr := claim.waiter.Wait(ctx)
-		if waitErr != nil || !ok || encoded == nil {
-			return waitErr
-		}
-		return s.sendCachedRPCResult(ctx, c, encoded)
-	case rpcResultAcquireOwner:
-		// Ownership transfers to the queued task only after commit succeeds.
-	default:
-		return ErrRPCResultFlightInvalid
-	}
-	owner := claim.owner
-	transferred := false
-	defer func() {
-		if !transferred {
-			owner.Abort()
-		}
-	}()
-	// 两级条数/字节预算必须先于 Copy：对抗客户端不能用大量满尺寸请求在“判断队列满”
-	// 之前制造一轮无上限的临时 body 分配。reservation 在 commit/abort 间唯一持有预算。
-	reservation, err := c.reserveInboundRPCBatch(ctx, []inboundRPCSpec{{method: method, size: request.Len()}})
-	if err != nil {
-		return s.handleInboundRPCAdmissionError(ctx, c, msgID, method, err)
-	}
-	defer reservation.abort()
-	body := request.Copy()
-	err = reservation.commit([]inboundRPC{s.newInboundRPCTask(c, msgID, method, body, owner)})
-	transferred = err == nil
-	return s.handleInboundRPCAdmissionError(ctx, c, msgID, method, err)
-}
-
 // newInboundRPCTask builds the exactly-once timeout/result gate shared by the
 // single-message and atomic container-batch admission paths. body must already
 // be an independently owned, budgeted copy.
@@ -675,7 +620,7 @@ func (s *Server) newInboundRPCTask(c *Conn, msgID int64, method string, body []b
 		run: func(taskCtx context.Context) error {
 			// body 是预算成功后生成的独立副本，且每个任务只 run 一次，
 			// 无需再 append 拷贝；直接复用，省掉一份 inbound 在途内存。
-			if err := s.handleRPC(taskCtx, c, msgID, method, &bin.Buffer{Buf: body}); err != nil {
+			if err := s.handleRPC(taskCtx, c, msgID, method, &bin.Buffer{Buf: body}, owner); err != nil {
 				fields := []zap.Field{
 					zap.Int64("msg_id", msgID),
 					zap.String("auth_key_id", c.authKeyHex),
@@ -711,24 +656,37 @@ func (s *Server) handleInboundRPCAdmissionError(ctx context.Context, c *Conn, ms
 }
 
 // handleRPC 把明文 RPC 请求交给 RPC 路由，并将结果或错误包成 rpc_result 回发。
-func (s *Server) handleRPC(ctx context.Context, c *Conn, msgID int64, method string, b *bin.Buffer) error {
+func (s *Server) handleRPC(ctx context.Context, c *Conn, msgID int64, method string, b *bin.Buffer, owner *rpcResultOwnerLease) error {
 	if s.rpc == nil {
 		if err := ctx.Err(); err != nil {
 			return err
 		}
 		s.log.Warn("No RPC handler configured", zap.String("method", method))
-		return s.sendResult(ctx, c, msgID, &mt.RPCError{
+		return s.publishRPCResult(c, msgID, method, owner, &mt.RPCError{
 			ErrorCode:    500,
 			ErrorMessage: "NOT_IMPLEMENTED",
-		})
+		}, nil)
 	}
 
 	ctx = postresponse.WithCallbacks(ctx)
 	ctx, dbStats := dbtrace.WithStats(ctx)
 	start := s.clock.Now()
-	result, err := s.rpc.Dispatch(ctx, c.authKeyID, c.sessionID, b)
+	effectiveMethod := method
+	var (
+		result bin.Encoder
+		err    error
+	)
+	if detailed, ok := s.rpc.(RPCHandlerWithMethod); ok {
+		var innerMethod string
+		result, innerMethod, err = detailed.DispatchWithMethod(ctx, c.authKeyID, c.sessionID, b)
+		if innerMethod != "" {
+			effectiveMethod = innerMethod
+		}
+	} else {
+		result, err = s.rpc.Dispatch(ctx, c.authKeyID, c.sessionID, b)
+	}
 	dur := s.clock.Now().Sub(start)
-	s.metrics.RPCHandled(method, dur, err)
+	s.metrics.RPCHandled(effectiveMethod, dur, err)
 	// 刷新本连接协商 layer（invokeWithLayer/initConnection 已被 Dispatch 处理并登记），
 	// 供 rpc_result 与后续 push 出站降级使用。仅在确实观测到 layer 时更新——缓存被驱逐
 	// 时 NegotiatedLayer 返回 ok=false，此时必须保留连接已记住的 layer，绝不覆盖成默认值，
@@ -739,12 +697,15 @@ func (s *Server) handleRPC(ctx context.Context, c *Conn, msgID int64, method str
 
 	fields := make([]zap.Field, 0, 12)
 	fields = append(fields,
-		zap.String("method", method),
+		zap.String("method", effectiveMethod),
 		zap.String("auth_key_id", c.authKeyHex),
 		zap.Int64("session_id", c.sessionID),
 		zap.Int64("msg_id", msgID),
 		zap.Duration("dur", dur),
 	)
+	if effectiveMethod != method {
+		fields = append(fields, zap.String("outer_method", method))
+	}
 	if businessAuthKeyHex, ok := c.BusinessAuthKeyHex(); ok {
 		fields = append(fields, zap.String("business_auth_key_id", businessAuthKeyHex))
 	}
@@ -767,33 +728,12 @@ func (s *Server) handleRPC(ctx context.Context, c *Conn, msgID int64, method str
 			terminal = &mt.RPCError{ErrorCode: 500, ErrorMessage: "RPC_TIMEOUT"}
 		}
 		if terminal != nil {
-			if c.isRetired() || !c.isPhysicalTransportCurrentOpen() {
-				// Replacement/shutdown already fenced this logical generation. Cache-only
-				// publication is safe and lets the replacement join the completed flight.
-				if encoded, encodeErr := s.encodeRPCResult(c, msgID, terminal); encodeErr != nil {
-					s.log.Warn("Encode canceled RPC result for replay failed", append(fields, zap.Error(encodeErr))...)
-				} else {
-					s.storeRPCResult(c, msgID, encoded)
+			var after func()
 			if runPostResponse {
-						postresponse.Run(context.WithoutCancel(ctx))
-					}
-				}
-			} else {
-				// An individual RPC deadline can expire while the physical connection is
-				// still healthy. Use a fresh bounded delivery context; publishing cache-only
-				// here would strand same-Conn duplicates behind an ACK with no result.
-				writeTimeout := c.writeTimeout
-				if writeTimeout <= 0 || writeTimeout > 5*time.Second {
-					writeTimeout = 5 * time.Second
-				}
-				responseCtx, cancel := context.WithTimeout(context.Background(), writeTimeout)
-				sendErr := s.sendResult(responseCtx, c, msgID, terminal)
-				cancel()
-				if sendErr != nil {
-					s.log.Debug("Send canceled RPC result failed", append(fields, zap.Error(sendErr))...)
-				} else if runPostResponse {
-					postresponse.Run(context.WithoutCancel(ctx))
+				after = postresponse.Take(context.WithoutCancel(ctx))
 			}
+			if sendErr := s.publishRPCResult(c, msgID, effectiveMethod, owner, terminal, after); sendErr != nil {
+				s.log.Debug("Publish canceled RPC result failed", append(fields, zap.Error(sendErr))...)
 			}
 		}
 		cancelFields := append(fields, zap.NamedError("context_error", ctxErr))
@@ -808,23 +748,126 @@ func (s *Server) handleRPC(ctx context.Context, c *Conn, msgID int64, method str
 		var rpcErr *tgerr.Error
 		if errors.As(err, &rpcErr) {
 			s.log.Info("RPC error", append(fields, zap.Int("code", rpcErr.Code), zap.String("error", rpcErr.Message))...)
-			return s.sendResult(ctx, c, msgID, &mt.RPCError{
+			return s.publishRPCResult(c, msgID, effectiveMethod, owner, &mt.RPCError{
 				ErrorCode:    rpcErr.Code,
 				ErrorMessage: rpcErr.Message,
-			})
+			}, nil)
 		}
 		s.log.Info("RPC internal error", append(fields, zap.Error(err))...)
-		return s.sendResult(ctx, c, msgID, &mt.RPCError{
+		return s.publishRPCResult(c, msgID, effectiveMethod, owner, &mt.RPCError{
 			ErrorCode:    500,
 			ErrorMessage: "INTERNAL",
-		})
+		}, nil)
 	}
 
 	s.log.Info("RPC handled", fields...)
-	if err := s.sendResult(ctx, c, msgID, result); err != nil {
+	return s.publishRPCResult(c, msgID, effectiveMethod, owner, result, postresponse.Take(ctx))
+}
+
+// publishRPCResult ends the inbound worker's ownership at bounded egress
+// admission. Physical delivery, fencing, completed-cache publication and the
+// post-response hook are thereafter owned by the single outbound actor.
+func (s *Server) publishRPCResult(
+	c *Conn,
+	reqMsgID int64,
+	method string,
+	owner *rpcResultOwnerLease,
+	result bin.Encoder,
+	afterDelivered func(),
+) error {
+	if result == nil {
+		result = &mt.RPCError{ErrorCode: 500, ErrorMessage: "INTERNAL"}
+	}
+	prepareTimeout := c.writeTimeout
+	if prepareTimeout <= 0 || prepareTimeout > 5*time.Second {
+		prepareTimeout = 5 * time.Second
+	}
+	prepareCtx, cancel := context.WithTimeout(context.Background(), prepareTimeout)
+	defer cancel()
+	encoded, err := s.encodeRPCResultContext(prepareCtx, c, reqMsgID, result)
+	if err != nil {
+		s.log.Warn("Encode RPC result failed; publishing INTERNAL",
+			zap.String("method", method), zap.Int64("req_msg_id", reqMsgID), zap.Error(err))
+		afterDelivered = nil
+		encoded, err = s.encodeRPCResultContext(prepareCtx, c, reqMsgID, &mt.RPCError{
+			ErrorCode: 500, ErrorMessage: "INTERNAL",
+		})
+		if err != nil {
+			c.fenceUndeliveredRPCResult()
 			return err
 		}
-	postresponse.Run(ctx)
+	}
+	if owner != nil && owner.Delivery() != nil {
+		// The owner-level delivery coordinator exists before the handler starts, so
+		// an initConnection rewrap can retarget even while result encoding is still
+		// pending. The encoded body itself remains immutable; the actor clones only
+		// the 12-byte rpc_result prefix when it snapshots the physical target.
+		encoded.delivery = owner.Delivery()
+	}
+	if afterDelivered != nil {
+		encoded.delivery.fn = afterDelivered
+	}
+	if owner != nil && !owner.HandOff() {
+		return ErrRPCResultFlightInvalid
+	}
+
+	priority := rpcResultPriority(method, encoded)
+	encoded.priority = priority
+	resultLogLevel := zap.DebugLevel
+	if encoded.compressed || priority == outboundPriorityCritical || priority == outboundPriorityBulk {
+		// Keep ordinary small RPCs at debug, but make convergence and bulk/gzip
+		// delivery visible in default service logs. These are the
+		// responses whose queueing and write latency diagnose startup Updating.
+		resultLogLevel = zap.InfoLevel
+	}
+	if metrics, ok := s.metrics.(RPCResultMetrics); ok {
+		metrics.RPCResultPrepared(method, priority.String(), encoded.uncompressedBytes, len(encoded.body), encoded.compressed)
+	}
+	egressStarted := time.Now()
+	terminal := func(deliveryErr error) {
+		latency := time.Since(egressStarted)
+		deliveredReqMsgID := encoded.writtenRequestID()
+		if metrics, ok := s.metrics.(RPCResultMetrics); ok {
+			metrics.RPCResultDelivered(method, latency, len(encoded.body), deliveryErr)
+		}
+		if deliveryErr != nil {
+			encoded.markReplayable()
+			c.fenceUndeliveredRPCResult()
+			s.storeRPCResult(c, reqMsgID, encoded)
+			if checked := s.log.Check(resultLogLevel, "RPC result delivery fenced for replay"); checked != nil {
+				checked.Write(
+					zap.String("method", method), zap.Int64("req_msg_id", reqMsgID),
+					zap.Int64("delivered_req_msg_id", deliveredReqMsgID),
+					zap.String("auth_key_id", c.authKeyHex), zap.Int64("session_id", c.sessionID),
+					zap.Int("wire_bytes", len(encoded.body)), zap.Bool("gzip", encoded.compressed),
+					zap.Error(deliveryErr))
+			}
+			return
+		}
+		s.storeRPCResult(c, reqMsgID, encoded)
+		encoded.markDelivered()
+		if checked := s.log.Check(resultLogLevel, "RPC result delivered"); checked != nil {
+			checked.Write(
+				zap.String("method", method), zap.Int64("req_msg_id", reqMsgID),
+				zap.Int64("delivered_req_msg_id", deliveredReqMsgID),
+				zap.String("auth_key_id", c.authKeyHex), zap.Int64("session_id", c.sessionID),
+				zap.Int("wire_bytes", len(encoded.body)), zap.Bool("gzip", encoded.compressed),
+				zap.Duration("egress_latency", latency))
+		}
+	}
+	encoded.markQueued()
+	if err := c.enqueueEncodedDelivery(prepareCtx, proto.MessageServerResponse, encoded, priority, terminal); err != nil {
+		// HandOff already made the egress path the terminal owner. No bytes were
+		// admitted, so fence this generation before publishing a replayable result.
+		terminal(err)
+		return err
+	}
+	if checked := s.log.Check(resultLogLevel, "RPC result admitted"); checked != nil {
+		checked.Write(
+			zap.String("method", method), zap.Int64("req_msg_id", reqMsgID),
+			zap.Int("wire_bytes", len(encoded.body)), zap.Int("inner_bytes", encoded.uncompressedBytes),
+			zap.Bool("gzip", encoded.compressed), zap.String("priority", priority.String()))
+	}
 	return nil
 }
 
@@ -833,13 +876,13 @@ func (s *Server) sendResult(ctx context.Context, c *Conn, reqMsgID int64, result
 	if result == nil {
 		result = &mt.RPCError{ErrorCode: 500, ErrorMessage: "INTERNAL"}
 	}
-	encoded, err := s.encodeRPCResult(c, reqMsgID, result)
+	encoded, err := s.encodeRPCResultContext(ctx, c, reqMsgID, result)
 	if err != nil {
 		// The business operation has already crossed atomic admission. Convert an
 		// invalid result encoder into one deterministic terminal RPC error instead of
 		// aborting the flight and allowing a reconnect to execute the operation again.
 		s.log.Warn("Encode RPC result failed; sending INTERNAL", zap.Int64("req_msg_id", reqMsgID), zap.Error(err))
-		encoded, err = s.encodeRPCResult(c, reqMsgID, &mt.RPCError{
+		encoded, err = s.encodeRPCResultContext(ctx, c, reqMsgID, &mt.RPCError{
 			ErrorCode:    500,
 			ErrorMessage: "INTERNAL",
 		})
@@ -854,12 +897,14 @@ func (s *Server) sendResult(ctx context.Context, c *Conn, reqMsgID int64, result
 		// (queue/context/scratch deadline); without this terminal barrier a later
 		// same-Conn duplicate would be ACKed while no result can ever arrive.
 		c.fenceUndeliveredRPCResult()
+		encoded.markReplayable()
 		s.storeRPCResult(c, reqMsgID, encoded)
 		return err
 	}
 	// On a live Conn, completed means the rpc_result has reached the reliable byte
 	// stream. Same-physical duplicates can therefore be ACK-only without data loss.
 	s.storeRPCResult(c, reqMsgID, encoded)
+	encoded.markDelivered()
 	return nil
 }
 
@@ -873,8 +918,10 @@ func (s *Server) sendCachedRPCResult(ctx context.Context, c *Conn, encoded *enco
 	}
 	if err := c.SendEncoded(ctx, proto.MessageServerResponse, encoded); err != nil {
 		c.fenceUndeliveredRPCResult()
+		encoded.markReplayable()
 		return err
 	}
+	encoded.markDelivered()
 	return nil
 }
 
@@ -884,30 +931,43 @@ func (s *Server) sendCachedRPCResult(ctx context.Context, c *Conn, encoded *enco
 // 降级改写字节时才重建整条消息。降级失败 fail-safe：记日志并发送 canonical 字节——
 // 宁可老客户端对个别长尾对象渲染异常，也不让连接/流崩。
 func (s *Server) encodeRPCResult(c *Conn, reqMsgID int64, result bin.Encoder) (*encodedOutboundMessage, error) {
-	const headerLen = 4 + 8 // rpc_result#f35c6d01 type_id + req_msg_id
-	var buf bin.Buffer
-	buf.PutID(proto.ResultTypeID)
-	buf.PutLong(reqMsgID)
-	if err := result.Encode(&buf); err != nil {
+	return s.encodeRPCResultContext(context.Background(), c, reqMsgID, result)
+}
+
+func (s *Server) encodeRPCResultContext(ctx context.Context, c *Conn, reqMsgID int64, result bin.Encoder) (*encodedOutboundMessage, error) {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	var inner bin.Buffer
+	// Terminal result preparation must survive physical-generation retirement:
+	// an overlapping replacement may already be waiting to replay this owner's
+	// result. Only the bounded preparation context, not the old socket stop, owns it.
+	if err := withOutboundEncodeSlot(ctx, nil, func() error {
+		return result.Encode(&inner)
+	}); err != nil {
 		return nil, fmt.Errorf("encode rpc result: %w", err)
 	}
+	innerBody := inner.Raw()
 	if layer := c.ClientLayer(); layer < layerwire.CanonicalLayer {
-		inner := buf.Buf[headerLen:]
-		if down, err := layerwire.Transcode(inner, layer); err != nil {
+		if down, err := layerwire.Transcode(innerBody, layer); err != nil {
 			s.log.Warn("layerwire downgrade failed; sending canonical rpc_result",
 				zap.Int("layer", layer), zap.Int64("req_msg_id", reqMsgID), zap.Error(err))
-		} else if !sameBacking(down, inner) {
-			var rebuilt bin.Buffer
-			rebuilt.PutID(proto.ResultTypeID)
-			rebuilt.PutLong(reqMsgID)
-			rebuilt.Put(down)
-			buf = rebuilt
+		} else {
+			innerBody = down
 		}
 	}
+
+	wireInner, compressed, err := encodeAdaptiveRPCResultInner(ctx, nil, innerBody)
+	if err != nil {
+		return nil, fmt.Errorf("compress rpc result: %w", err)
+	}
+	var out bin.Buffer
+	out.PutID(proto.ResultTypeID)
+	out.PutLong(reqMsgID)
+	out.Put(wireInner)
 	return &encodedOutboundMessage{
-		typeID:   proto.ResultTypeID,
-		body:     buf.Raw(),
-		reqMsgID: reqMsgID,
+		typeID: proto.ResultTypeID, body: out.Raw(), reqMsgID: reqMsgID,
+		compressed: compressed, uncompressedBytes: len(innerBody), delivery: newRPCResultDelivery(),
 	}, nil
 }
 

internal/mtprotoedge/inbound_preflight.go

@@ -34,7 +34,10 @@ const (
 	inboundItemDestroyAuthKey
 	inboundItemRPC
 	inboundItemCapacityError
-	inboundItemPendingRPC
+	// inboundItemRewrappedRPC is an initConnection retry whose exact inner TL
+	// request is already executing (or completed) under the client's old msg_id.
+	// It never dispatches business code a second time.
+	inboundItemRewrappedRPC
 	// inboundItemReplayRPC is a request first observed by this physical Conn whose
 	// terminal result already exists in the cross-connection cache. It is distinct
 	// from inboundItemDuplicate: a duplicate already present in this Conn's seen
@@ -71,6 +74,8 @@ type inboundPlan struct {
 	rpcReservation *inboundRPCBatchReservation
 	rpcTasks       []inboundRPC
 	rpcOwners      []*rpcResultOwnerLease
+	rewrapAliases  []*rpcRewrapAlias
+	rewrapIndices  []int
 }
 
 func (p *inboundPlan) close() {
@@ -85,12 +90,42 @@ func (p *inboundPlan) close() {
 		owner.Abort()
 	}
 	p.rpcOwners = nil
+	for _, alias := range p.rewrapAliases {
+		alias.releaseCandidate()
+		if alias != nil && alias.newOwner != nil {
+			alias.newOwner.Abort()
+		}
+	}
+	p.rewrapAliases = nil
+	p.rewrapIndices = nil
 	for i := len(p.releases) - 1; i >= 0; i-- {
 		p.releases[i]()
 	}
 	p.releases = nil
 }
 
+func (p *inboundPlan) commitRewrapAliases(s *Server) error {
+	if p == nil || len(p.rewrapAliases) == 0 {
+		return nil
+	}
+	for i, alias := range p.rewrapAliases {
+		if err := alias.activate(s); err != nil {
+			for _, pending := range p.rewrapAliases[i:] {
+				pending.releaseCandidate()
+				if pending != nil && pending.newOwner != nil {
+					pending.newOwner.Abort()
+				}
+			}
+			p.rewrapAliases = nil
+			p.rewrapIndices = nil
+			return err
+		}
+	}
+	p.rewrapAliases = nil
+	p.rewrapIndices = nil
+	return nil
+}
+
 func (p *inboundPlan) commitRPCBatch() error {
 	if p == nil || p.rpcReservation == nil {
 		return nil
@@ -624,6 +659,7 @@ func (s *Server) prepareInboundRPCBatch(ctx context.Context, c *Conn, plan *inbo
 	var specs []inboundRPCSpec
 	var ownersInPlan map[int64]*rpcResultOwnerLease
 	flightCapacity := false
+	clearedPostInitCandidates := false
 	for i := range plan.items {
 		item := &plan.items[i]
 		if item.kind != inboundItemRPC && item.kind != inboundItemDuplicate {
@@ -638,6 +674,71 @@ func (s *Server) prepareInboundRPCBatch(ctx context.Context, c *Conn, plan *inbo
 			continue
 		}
 		method := s.typeName(item.typeID)
+		init, isInitRewrap := decodeRPCRewrapInit(item.body)
+		if isInitRewrap {
+			firstInit := !c.rpcRewrapInitialized.Swap(true)
+			c.SetClientLayer(init.layer)
+			if candidate := s.rpcRewrap.claim(c, init.inner); candidate != nil {
+				claim, err := s.rpcResults.Acquire(c.authKeyID, c.sessionID, item.msgID)
+				if errors.Is(err, ErrRPCResultFlightCapacity) {
+					s.rpcRewrap.release(candidate)
+					c.metrics.InboundRPCDropped(candidate.method, "flight_capacity")
+					flightCapacity = true
+					item.kind = inboundItemCapacityError
+					continue
+				}
+				if err != nil {
+					s.rpcRewrap.release(candidate)
+					return err
+				}
+				switch claim.state {
+				case rpcResultAcquireCompleted:
+					s.rpcRewrap.commit(candidate)
+					item.kind = inboundItemReplayRPC
+					item.payload = claim.encoded
+				case rpcResultAcquirePending:
+					s.rpcRewrap.commit(candidate)
+					item.kind = inboundItemRewrappedRPC
+					item.payload = claim.waiter
+					plan.rewrapAliases = append(plan.rewrapAliases, &rpcRewrapAlias{
+						conn: c, newReqID: item.msgID, method: candidate.method,
+						oldWaiter: claim.waiter, observeInit: firstInit, init: init,
+					})
+					plan.rewrapIndices = append(plan.rewrapIndices, i)
+				case rpcResultAcquireOwner:
+					if ownersInPlan == nil {
+						ownersInPlan = make(map[int64]*rpcResultOwnerLease)
+					}
+					ownersInPlan[item.msgID] = claim.owner
+					item.kind = inboundItemRewrappedRPC
+					item.payload = claim.owner
+					plan.rewrapAliases = append(plan.rewrapAliases, &rpcRewrapAlias{
+						conn: c, newReqID: item.msgID, method: candidate.method,
+						oldWaiter: candidate.waiter, newOwner: claim.owner,
+						sourceConn: candidate.source, sourceOwner: candidate.owner,
+						observeInit: firstInit, init: init,
+						candidate: candidate, registry: s.rpcRewrap,
+					})
+					plan.rewrapIndices = append(plan.rewrapIndices, i)
+				default:
+					s.rpcRewrap.release(candidate)
+					return ErrRPCResultFlightInvalid
+				}
+				s.log.Info("RPC init rewrap matched",
+					zap.String("method", candidate.method),
+					zap.Int64("old_req_msg_id", candidate.reqMsgID),
+					zap.Int64("new_req_msg_id", item.msgID),
+					zap.Bool("same_connection", candidate.source == c),
+					zap.String("auth_key_id", c.authKeyHex), zap.Int64("session_id", c.sessionID))
+				continue
+			}
+		} else if c.rpcRewrapInitialized.Load() && !clearedPostInitCandidates {
+			// A naked request after this connection has observed initConnection is
+			// event-level proof that the client finished moving its old running set.
+			// Retire any unmatched candidates without a timer.
+			s.rpcRewrap.clearSession(c)
+			clearedPostInitCandidates = true
+		}
 		claim, err := s.rpcResults.Acquire(c.authKeyID, c.sessionID, item.msgID)
 		if errors.Is(err, ErrRPCResultFlightCapacity) {
 			if item.kind == inboundItemRPC {
@@ -669,8 +770,11 @@ func (s *Server) prepareInboundRPCBatch(ctx context.Context, c *Conn, plan *inbo
 				item.kind = inboundItemDuplicate
 				item.payload = nil
 			} else {
-				item.kind = inboundItemPendingRPC
+				item.kind = inboundItemRewrappedRPC
 				item.payload = claim.waiter
+				plan.rewrapAliases = append(plan.rewrapAliases, &rpcRewrapAlias{
+					conn: c, newReqID: item.msgID, method: method, oldWaiter: claim.waiter,
+				})
 			}
 		case rpcResultAcquireOwner:
 			if item.kind == inboundItemDuplicate {
@@ -689,6 +793,9 @@ func (s *Server) prepareInboundRPCBatch(ctx context.Context, c *Conn, plan *inbo
 			item.payload = claim.owner
 			indices = append(indices, i)
 			specs = append(specs, inboundRPCSpec{method: method, size: len(item.body)})
+			if !c.rpcRewrapInitialized.Load() && !isInitRewrap {
+				s.rpcRewrap.register(c, item.body, item.msgID, method, claim.owner)
+			}
 		default:
 			return ErrRPCResultFlightInvalid
 		}
@@ -700,6 +807,17 @@ func (s *Server) prepareInboundRPCBatch(ctx context.Context, c *Conn, plan *inbo
 		for _, index := range indices {
 			plan.items[index].kind = inboundItemCapacityError
 		}
+		for _, index := range plan.rewrapIndices {
+			plan.items[index].kind = inboundItemCapacityError
+		}
+		for _, alias := range plan.rewrapAliases {
+			alias.releaseCandidate()
+			if alias.newOwner != nil {
+				alias.newOwner.Abort()
+			}
+		}
+		plan.rewrapAliases = nil
+		plan.rewrapIndices = nil
 		return nil
 	}
 	if len(specs) == 0 {
@@ -712,6 +830,17 @@ func (s *Server) prepareInboundRPCBatch(ctx context.Context, c *Conn, plan *inbo
 			for _, index := range indices {
 				plan.items[index].kind = inboundItemCapacityError
 			}
+			for _, index := range plan.rewrapIndices {
+				plan.items[index].kind = inboundItemCapacityError
+			}
+			for _, alias := range plan.rewrapAliases {
+				alias.releaseCandidate()
+				if alias.newOwner != nil {
+					alias.newOwner.Abort()
+				}
+			}
+			plan.rewrapAliases = nil
+			plan.rewrapIndices = nil
 			return nil
 		}
 		return err
@@ -751,10 +880,10 @@ func (s *Server) executeInboundPlan(ctx context.Context, cs *connState, c *Conn,
 			} else if err := s.replayRPCResultByRequest(ctx, c, item.msgID); err != nil {
 				return err
 			}
-		case inboundItemPendingRPC:
-			// Wait only after this plan's fresh RPC batch has become runnable; see
-			// executePendingRPCReplays. Blocking here could otherwise deadlock on
-			// an owner appended by the same container.
+		case inboundItemRewrappedRPC:
+			// Activation is deferred until every session/control barrier has
+			// committed. It subscribes to the original result event and never waits
+			// or dispatches the business handler again.
 			continue
 		case inboundItemPing:
 			if err := s.sendPong(ctx, c, item.msgID, item.payload.(mt.PingRequest).PingID); err != nil {
@@ -842,41 +971,3 @@ func (s *Server) executeInboundPlan(ctx context.Context, cs *connState, c *Conn,
 	}
 	return nil
 }
-
-// executePendingRPCReplays joins owners already running on another physical
-// connection for the same MTProto session. It never dispatches business code:
-// owner Put publishes the immutable result to every waiter; owner Abort leaves
-// the client free to retry after the old execution has definitely stopped.
-func (s *Server) executePendingRPCReplays(ctx context.Context, c *Conn, plan *inboundPlan) error {
-	for _, item := range plan.items {
-		if item.kind != inboundItemPendingRPC {
-			continue
-		}
-		waiter, _ := item.payload.(*rpcResultWaiter)
-		if waiter == nil {
-			continue
-		}
-		encoded, ok, err := waiter.Wait(ctx)
-		if err != nil {
-			return err
-		}
-		if !ok || encoded == nil {
-			// The old owner stopped without publishing a result (normally because
-			// replacement cancellation reached the handler before it committed).
-			// A fresh-connection item still owns the decoded request body, so reacquire
-			// only after the prior flight is definitively gone. This is sequential
-			// retry, never concurrent business execution. Same-Conn seen duplicates
-			// have no body here and rely on the client's ordinary resend path.
-			if len(item.body) > 0 {
-				if err := s.enqueueRPC(ctx, c, item.msgID, item.typeID, &bin.Buffer{Buf: item.body}); err != nil {
-					return err
-				}
-			}
-			continue
-		}
-		if err := s.sendCachedRPCResult(ctx, c, encoded); err != nil {
-			return err
-		}
-	}
-	return nil
-}

internal/mtprotoedge/metrics.go

@@ -30,6 +30,24 @@ type Metrics interface {
 	OutboundQueueWait(len, cap int)
 }
 
+// RPCResultMetrics is an optional extension for the detached response pipeline.
+// Keeping it separate preserves lightweight embedders while production exporters
+// can observe preparation/compression and end-to-end delivery independently from
+// business handler latency.
+type RPCResultMetrics interface {
+	RPCResultPrepared(method, priority string, innerBytes, wireBytes int, compressed bool)
+	RPCResultDelivered(method string, egressLatency time.Duration, wireBytes int, err error)
+}
+
+// ConnectionIntakeMetrics is an optional extension for the pre-session
+// connection pipeline. stage is one of raw_accept, mux_sniff, mux_delivery,
+// transport_dispatch, transport_promote, or first_frame; outcome is a bounded
+// value suitable for metrics labels. Remote addresses are deliberately kept in
+// structured logs only so exporters cannot create unbounded cardinality.
+type ConnectionIntakeMetrics interface {
+	ConnectionIntake(stage, outcome string, duration time.Duration)
+}
+
 // NopMetrics 是 Metrics 的空实现。
 type NopMetrics struct{}
 

internal/mtprotoedge/outbound.go

@@ -38,6 +38,8 @@ const (
 	// 慢消费者继续由 best-effort timeout + durable difference 降级。
 	defaultOutboundQueueSize         = 128
 	defaultOutboundControlQueueSize  = 32
+	defaultOutboundCriticalQueueSize = 16
+	defaultOutboundBulkQueueSize     = 16
 	defaultOutboundTrackedMaxBytes   = int64(512 << 20) // 512 MiB / Server
 	defaultOutboundControlMaxBytes   = int64(64 << 20)  // ack/state/resend vectors / Server
 	// requiredControlMaxWait bounds protocol barriers such as new_session_created from
@@ -67,9 +69,27 @@ const (
 	outboundResendByRequest
 )
 
+type outboundPriority uint8
+
+const (
+	outboundPriorityNormal outboundPriority = iota
+	outboundPriorityCritical
+	outboundPriorityBulk
+	outboundPriorityControl
+)
+
+const (
+	// Large responses are scheduled separately so a startup prefetch cannot sit
+	// ahead of an already-prepared session convergence result. The threshold is
+	// applied after layer conversion and adaptive gzip.
+	bulkOutboundThreshold = 64 << 10
+	maxOrdinaryBeforeBulk = 16
+)
+
 type outboundOp struct {
 	kind     outboundOpKind
 	control  bool
+	priority outboundPriority
 	ctx      context.Context
 	msgType  proto.MessageType
 	msg      bin.Encoder
@@ -83,12 +103,160 @@ type outboundOp struct {
 	reqMsgID          int64
 	enqueuedAt        time.Time
 	done              chan outboundResult
+	// terminal is owned by the outbound actor after successful queue admission.
+	// It resolves detached RPC-result ownership on every physical terminal path.
+	terminal func(error)
 }
 
 type encodedOutboundMessage struct {
 	body              []byte
 	typeID            uint32
 	reqMsgID          int64
+	priority          outboundPriority
+	delivery          *rpcResultDelivery
+	compressed        bool
+	uncompressedBytes int
+}
+
+type rpcResultDeliveryState uint32
+
+const (
+	rpcResultDeliveryPrepared rpcResultDeliveryState = iota + 1
+	rpcResultDeliveryQueued
+	rpcResultDeliveryWriting
+	rpcResultDeliveryReplayable
+	rpcResultDeliveryDelivered
+)
+
+type rpcResultDelivery struct {
+	state atomic.Uint32
+	mu    sync.Mutex
+	// targetReqMsgID may change only before the outbound actor enters writing.
+	// writtenReqMsgID is the actor's immutable snapshot for the physical frame.
+	targetReqMsgID  int64
+	writtenReqMsgID int64
+	once            sync.Once
+	fn              func()
+}
+
+func newRPCResultDelivery(reqMsgID ...int64) *rpcResultDelivery {
+	d := &rpcResultDelivery{}
+	if len(reqMsgID) > 0 {
+		d.targetReqMsgID = reqMsgID[0]
+	}
+	d.state.Store(uint32(rpcResultDeliveryPrepared))
+	return d
+}
+
+func (m *encodedOutboundMessage) deliveryState() rpcResultDeliveryState {
+	if m == nil || m.delivery == nil {
+		return 0
+	}
+	return rpcResultDeliveryState(m.delivery.state.Load())
+}
+
+func (m *encodedOutboundMessage) markQueued() {
+	if m == nil || m.delivery == nil {
+		return
+	}
+	m.delivery.mu.Lock()
+	if m.deliveryState() == rpcResultDeliveryPrepared {
+		m.delivery.state.Store(uint32(rpcResultDeliveryQueued))
+	}
+	m.delivery.mu.Unlock()
+}
+
+// beginWriting linearizes retargeting against the sole outbound actor. The
+// returned req_msg_id is immutable for this physical write.
+func (m *encodedOutboundMessage) beginWriting() int64 {
+	if m == nil || m.delivery == nil {
+		if m == nil {
+			return 0
+		}
+		return m.reqMsgID
+	}
+	m.delivery.mu.Lock()
+	if m.delivery.targetReqMsgID == 0 {
+		m.delivery.targetReqMsgID = m.reqMsgID
+	}
+	m.delivery.writtenReqMsgID = m.delivery.targetReqMsgID
+	m.delivery.state.Store(uint32(rpcResultDeliveryWriting))
+	target := m.delivery.writtenReqMsgID
+	m.delivery.mu.Unlock()
+	return target
+}
+
+func (m *encodedOutboundMessage) tryRetarget(reqMsgID int64) bool {
+	if m == nil || m.delivery == nil || reqMsgID == 0 {
+		return false
+	}
+	m.delivery.mu.Lock()
+	defer m.delivery.mu.Unlock()
+	state := m.deliveryState()
+	if state != rpcResultDeliveryPrepared && state != rpcResultDeliveryQueued {
+		return false
+	}
+	m.delivery.targetReqMsgID = reqMsgID
+	return true
+}
+
+func (m *encodedOutboundMessage) writtenRequestID() int64 {
+	if m == nil || m.delivery == nil {
+		if m == nil {
+			return 0
+		}
+		return m.reqMsgID
+	}
+	m.delivery.mu.Lock()
+	id := m.delivery.writtenReqMsgID
+	if id == 0 {
+		id = m.delivery.targetReqMsgID
+	}
+	m.delivery.mu.Unlock()
+	if id == 0 {
+		return m.reqMsgID
+	}
+	return id
+}
+
+func (m *encodedOutboundMessage) markReplayable() {
+	if m == nil || m.delivery == nil {
+		return
+	}
+	m.delivery.mu.Lock()
+	if m.deliveryState() != rpcResultDeliveryDelivered {
+		m.delivery.state.Store(uint32(rpcResultDeliveryReplayable))
+	}
+	m.delivery.mu.Unlock()
+}
+
+func (m *encodedOutboundMessage) markDelivered() {
+	if m == nil || m.delivery == nil {
+		return
+	}
+	m.delivery.mu.Lock()
+	m.delivery.state.Store(uint32(rpcResultDeliveryDelivered))
+	m.delivery.mu.Unlock()
+	if m.delivery.fn != nil {
+		m.delivery.once.Do(func() { scheduleRPCDeliveryHook(m.delivery.fn) })
+	}
+}
+
+func cloneRPCResultForRequest(encoded *encodedOutboundMessage, reqMsgID int64, shareDelivery bool) (*encodedOutboundMessage, error) {
+	if encoded == nil || encoded.typeID != proto.ResultTypeID || len(encoded.body) < 12 || reqMsgID == 0 {
+		return nil, errors.New("invalid rpc_result retarget")
+	}
+	body := append([]byte(nil), encoded.body...)
+	binary.LittleEndian.PutUint64(body[4:12], uint64(reqMsgID))
+	delivery := newRPCResultDelivery(reqMsgID)
+	if shareDelivery {
+		delivery = encoded.delivery
+	}
+	return &encodedOutboundMessage{
+		body: body, typeID: encoded.typeID, reqMsgID: reqMsgID,
+		priority: encoded.priority, delivery: delivery, compressed: encoded.compressed,
+		uncompressedBytes: encoded.uncompressedBytes,
+	}, nil
 }
 
 type outboundResult struct {
@@ -314,12 +482,20 @@ func (c *Conn) startOutbound() {
 	if c.outboundQueueSize <= 0 {
 		c.outboundQueueSize = defaultOutboundQueueSize
 	}
+	if c.outboundQueueSize < 3 {
+		c.outboundQueueSize = 3
+	}
 	if c.outboundControlQueueSize <= 0 {
 		c.outboundControlQueueSize = defaultOutboundControlQueueSize
 	}
 	c.ensureOutboundTrackedBudget()
-	c.outbound = make(chan outboundOp, c.outboundQueueSize)
+	criticalSize := min(defaultOutboundCriticalQueueSize, max(1, c.outboundQueueSize/8))
+	bulkSize := min(defaultOutboundBulkQueueSize, max(1, c.outboundQueueSize/8))
+	normalSize := c.outboundQueueSize - criticalSize - bulkSize
+	c.outbound = make(chan outboundOp, normalSize)
 	c.outboundControl = make(chan outboundOp, c.outboundControlQueueSize)
+	c.outboundCritical = make(chan outboundOp, criticalSize)
+	c.outboundBulk = make(chan outboundOp, bulkSize)
 	c.outboundStop = make(chan struct{})
 	c.outboundDone = make(chan struct{})
 	go c.outboundLoop()
@@ -525,8 +701,9 @@ func (c *Conn) sendBestEffort(ctx context.Context, t proto.MessageType, msg bin.
 	op.enqueuedAt = time.Now()
 	// 快路径：非阻塞入队。fan-out 每 (conn × push) 都走这里，队列有空位时不为
 	// 本次推送分配任何 timer（此前 timeout>0 无条件 WithTimeout，稳态白建 timer）。
+	q := c.outboundQueue(op)
 	select {
-	case c.outbound <- op:
+	case q <- op:
 		return nil
 	case <-c.outboundStop:
 		op.releaseReservation(c.outboundTrackedBudget)
@@ -538,7 +715,7 @@ func (c *Conn) sendBestEffort(ctx context.Context, t proto.MessageType, msg bin.
 		c.metrics.OutboundDropped("push_queue_full")
 		return ErrOutboundQueueFull
 	}
-	c.metrics.OutboundQueueWait(len(c.outbound), cap(c.outbound))
+	c.metrics.OutboundQueueWait(len(q), cap(q))
 	if ctx == nil {
 		ctx = context.Background()
 	}
@@ -549,7 +726,7 @@ func (c *Conn) sendBestEffort(ctx context.Context, t proto.MessageType, msg bin.
 		timeoutC = timer.C
 	}
 	select {
-	case c.outbound <- op:
+	case q <- op:
 		return nil
 	case <-timeoutC:
 		op.releaseReservation(c.outboundTrackedBudget)
@@ -572,6 +749,41 @@ func (c *Conn) SendEncoded(ctx context.Context, t proto.MessageType, encoded *en
 	return c.sendOutbound(ctx, t, nil, encoded, false)
 }
 
+// enqueueEncodedDelivery transfers an immutable body to the bounded egress actor
+// and returns after queue admission, not after socket I/O. terminal becomes actor-
+// owned only on success and is invoked for write success, write failure, or drain.
+func (c *Conn) enqueueEncodedDelivery(
+	ctx context.Context,
+	t proto.MessageType,
+	encoded *encodedOutboundMessage,
+	priority outboundPriority,
+	terminal func(error),
+) error {
+	if c.outbound == nil || c.outboundControl == nil || c.outboundCritical == nil || c.outboundBulk == nil {
+		return ErrConnClosed
+	}
+	op, err := c.newOutboundSendOp(ctx, t, nil, encoded, false)
+	if err != nil {
+		c.failOutboundBudget(err)
+		return err
+	}
+	if !c.beginOutboundEnqueue() {
+		op.releaseReservation(c.outboundTrackedBudget)
+		return ErrConnClosed
+	}
+	op.priority = priority
+	op.ctx = context.Background()
+	op.enqueuedAt = time.Now()
+	op.terminal = terminal
+	if err := c.enqueueOutboundRegistered(ctx, op); err != nil {
+		op.releaseReservation(c.outboundTrackedBudget)
+		c.endOutboundEnqueue()
+		return err
+	}
+	c.endOutboundEnqueue()
+	return nil
+}
+
 func (c *Conn) sendOutbound(ctx context.Context, t proto.MessageType, msg bin.Encoder, encoded *encodedOutboundMessage, control bool) error {
 	if c.outbound == nil || c.outboundControl == nil {
 		return ErrConnClosed
@@ -774,10 +986,7 @@ func (c *Conn) enqueueOutboundRegistered(ctx context.Context, op outboundOp) err
 	if c.isRetired() {
 		return ErrConnClosed
 	}
-	q := c.outbound
-	if op.control {
-		q = c.outboundControl
-	}
+	q := c.outboundQueue(op)
 	select {
 	case q <- op:
 		return nil
@@ -798,6 +1007,20 @@ func (c *Conn) enqueueOutboundRegistered(ctx context.Context, op outboundOp) err
 	}
 }
 
+func (c *Conn) outboundQueue(op outboundOp) chan outboundOp {
+	if op.control || op.priority == outboundPriorityControl {
+		return c.outboundControl
+	}
+	switch op.priority {
+	case outboundPriorityCritical:
+		return c.outboundCritical
+	case outboundPriorityBulk:
+		return c.outboundBulk
+	default:
+		return c.outbound
+	}
+}
+
 func (c *Conn) beginOutboundEnqueue() bool {
 	c.outboundEnqueueMu.Lock()
 	defer c.outboundEnqueueMu.Unlock()
@@ -814,6 +1037,7 @@ func (c *Conn) endOutboundEnqueue() {
 
 func (c *Conn) outboundLoop() {
 	state := newOutboundState(c.outboundTrackedBudget)
+	ordinarySinceBulk := 0
 	defer func() {
 		// pending frames belong exclusively to this actor. Releasing after drain ensures no
 		// resend path can race the final budget return and no Conn body survives actor exit.
@@ -826,8 +1050,11 @@ func (c *Conn) outboundLoop() {
 			c.drainOutbound()
 			return
 		}
-		select {
-		case op := <-c.outboundControl:
+		op, ok := c.nextOutboundOp(&ordinarySinceBulk)
+		if !ok {
+			c.drainOutbound()
+			return
+		}
 		if c.isRetired() {
 			op.releaseReservation(c.outboundTrackedBudget)
 			op.finish(outboundResult{err: ErrConnClosed})
@@ -841,37 +1068,55 @@ func (c *Conn) outboundLoop() {
 			c.drainOutbound()
 			return
 		}
-			continue
-		default:
 	}
+}
+
+// nextOutboundOp applies the connection-wide egress policy without introducing
+// another writer. Required protocol controls stay strict, convergence RPCs pass
+// ordinary/bulk work, and a bounded ordinary burst guarantees bulk progress.
+func (c *Conn) nextOutboundOp(ordinarySinceBulk *int) (outboundOp, bool) {
+	try := func(q <-chan outboundOp) (outboundOp, bool) {
+		select {
+		case op := <-q:
+			return op, true
+		default:
+			return outboundOp{}, false
+		}
+	}
+	if op, ok := try(c.outboundControl); ok {
+		return op, true
+	}
+	if op, ok := try(c.outboundCritical); ok {
+		return op, true
+	}
+	if *ordinarySinceBulk >= maxOrdinaryBeforeBulk {
+		if op, ok := try(c.outboundBulk); ok {
+			*ordinarySinceBulk = 0
+			return op, true
+		}
+	}
+	if op, ok := try(c.outbound); ok {
+		*ordinarySinceBulk++
+		return op, true
+	}
+	if op, ok := try(c.outboundBulk); ok {
+		*ordinarySinceBulk = 0
+		return op, true
+	}
+
 	select {
 	case <-c.outboundStop:
-			c.drainOutbound()
-			return
+		return outboundOp{}, false
 	case op := <-c.outboundControl:
-			if c.isRetired() {
-				op.releaseReservation(c.outboundTrackedBudget)
-				op.finish(outboundResult{err: ErrConnClosed})
-				c.signalOutboundStop()
-				c.drainOutbound()
-				return
-			}
-			c.handleOutboundOp(state, op)
+		return op, true
+	case op := <-c.outboundCritical:
+		return op, true
 	case op := <-c.outbound:
-			if c.isRetired() {
-				op.releaseReservation(c.outboundTrackedBudget)
-				op.finish(outboundResult{err: ErrConnClosed})
-				c.signalOutboundStop()
-				c.drainOutbound()
-				return
-			}
-			c.handleOutboundOp(state, op)
-		}
-		if c.isRetired() {
-			c.signalOutboundStop()
-			c.drainOutbound()
-			return
-		}
+		*ordinarySinceBulk++
+		return op, true
+	case op := <-c.outboundBulk:
+		*ordinarySinceBulk = 0
+		return op, true
 	}
 }
 
@@ -885,9 +1130,15 @@ func (c *Conn) drainOutbound() {
 		case op := <-c.outboundControl:
 			op.releaseReservation(c.outboundTrackedBudget)
 			op.finish(outboundResult{err: ErrConnClosed})
+		case op := <-c.outboundCritical:
+			op.releaseReservation(c.outboundTrackedBudget)
+			op.finish(outboundResult{err: ErrConnClosed})
 		case op := <-c.outbound:
 			op.releaseReservation(c.outboundTrackedBudget)
 			op.finish(outboundResult{err: ErrConnClosed})
+		case op := <-c.outboundBulk:
+			op.releaseReservation(c.outboundTrackedBudget)
+			op.finish(outboundResult{err: ErrConnClosed})
 		default:
 			return
 		}
@@ -902,7 +1153,11 @@ func (c *Conn) handleOutboundOp(state *outboundState, op outboundOp) {
 	case outboundSend:
 		c.handleOutboundSend(state, op)
 	case outboundAck:
-		state.ack(op.ids)
+		for _, reqMsgID := range state.ack(op.ids) {
+			if c.rpcResultAcked != nil {
+				c.rpcResultAcked(c, reqMsgID)
+			}
+		}
 	case outboundQueryState:
 		op.finish(outboundResult{info: state.stateInfo(op.ids)})
 	case outboundResend:
@@ -917,7 +1172,17 @@ func (c *Conn) handleOutboundOp(state *outboundState, op outboundOp) {
 }
 
 func (c *Conn) handleOutboundSend(state *outboundState, op outboundOp) {
-	frame, err := c.buildFrame(op.ctx, op.msgType, op.msg, op.encoded)
+	var err error
+	if op.encoded != nil {
+		targetReqMsgID := op.encoded.beginWriting()
+		if targetReqMsgID != 0 && targetReqMsgID != op.encoded.reqMsgID {
+			op.encoded, err = cloneRPCResultForRequest(op.encoded, targetReqMsgID, true)
+		}
+	}
+	var frame *outboundFrame
+	if err == nil {
+		frame, err = c.buildFrame(op.ctx, op.msgType, op.msg, op.encoded)
+	}
 	reserved := op.reservedBytes
 	reservationBudget := op.reservationBudget
 	if reservationBudget == nil {
@@ -1018,6 +1283,9 @@ func (c *Conn) handleOutboundResendByRequest(state *outboundState, ctx context.C
 }
 
 func (op outboundOp) finish(res outboundResult) {
+	if op.terminal != nil {
+		op.terminal(res.err)
+	}
 	if op.done == nil {
 		return
 	}
@@ -1093,6 +1361,7 @@ func (c *Conn) newOutboundSendOp(ctx context.Context, t proto.MessageType, msg b
 			kind:              outboundSend,
 			msgType:           t,
 			encoded:           encoded,
+			priority:          classifyOutboundPriority(encoded, priorityControl),
 			reservedBytes:     bytes,
 			reservationBudget: budget,
 		}, nil
@@ -1112,11 +1381,25 @@ func (c *Conn) newOutboundSendOp(ctx context.Context, t proto.MessageType, msg b
 		kind:              outboundSend,
 		msgType:           t,
 		encoded:           encoded,
+		priority:          classifyOutboundPriority(encoded, priorityControl),
 		reservedBytes:     bytes,
 		reservationBudget: budget,
 	}, nil
 }
 
+func classifyOutboundPriority(encoded *encodedOutboundMessage, control bool) outboundPriority {
+	if control {
+		return outboundPriorityControl
+	}
+	if encoded != nil && encoded.priority != outboundPriorityNormal {
+		return encoded.priority
+	}
+	if encoded != nil && len(encoded.body) >= bulkOutboundThreshold {
+		return outboundPriorityBulk
+	}
+	return outboundPriorityNormal
+}
+
 func (c *Conn) outboundMessageBudget(typeID uint32, priorityControl bool) *outboundTrackedBudget {
 	if priorityControl || encodedControlFrame(typeID) {
 		return c.ensureOutboundControlTrackedBudget()
@@ -1210,7 +1493,11 @@ func (c *Conn) downgradedCloneContext(ctx context.Context, encoded *encodedOutbo
 	if sameBacking(down, encoded.body) {
 		return encoded // 直通：未变(mt.*/顶层未知)，无需拷贝或重算 typeID
 	}
-	out := &encodedOutboundMessage{body: down, typeID: encoded.typeID, reqMsgID: encoded.reqMsgID}
+	out := &encodedOutboundMessage{
+		body: down, typeID: encoded.typeID, reqMsgID: encoded.reqMsgID,
+		priority: encoded.priority, delivery: encoded.delivery, compressed: encoded.compressed,
+		uncompressedBytes: encoded.uncompressedBytes,
+	}
 	if id, e := (&bin.Buffer{Buf: down}).PeekID(); e == nil {
 		out.typeID = id
 	}
@@ -1535,8 +1822,16 @@ func (s *outboundState) addReserved(frame *outboundFrame) int {
 	return s.shrinkPending()
 }
 
-func (s *outboundState) ack(ids []int64) {
+func (s *outboundState) ack(ids []int64) []int64 {
+	var requestIDs []int64
 	for _, id := range ids {
+		frame, ok := s.pending[id]
+		if !ok {
+			continue
+		}
+		if frame.reqMsgID != 0 {
+			requestIDs = append(requestIDs, frame.reqMsgID)
+		}
 		if !s.removePending(id) {
 			continue
 		}
@@ -1545,6 +1840,7 @@ func (s *outboundState) ack(ids []int64) {
 	if len(s.order) > s.maxMessages*2 {
 		s.compactOrder()
 	}
+	return requestIDs
 }
 
 func (s *outboundState) stateInfo(ids []int64) []byte {

internal/mtprotoedge/outbound_test.go

@@ -397,8 +397,8 @@ func TestOutboundQueueBackingUsesSmallConfigurableBounds(t *testing.T) {
 		c := &Conn{metrics: NopMetrics{}}
 		c.startOutbound()
 		defer c.Close()
-		if got := cap(c.outbound); got != defaultOutboundQueueSize {
-			t.Fatalf("normal queue cap = %d, want %d", got, defaultOutboundQueueSize)
+		if got := cap(c.outbound) + cap(c.outboundCritical) + cap(c.outboundBulk); got != defaultOutboundQueueSize {
+			t.Fatalf("ordinary lane total cap = %d, want %d", got, defaultOutboundQueueSize)
 		}
 		if got := cap(c.outboundControl); got != defaultOutboundControlQueueSize {
 			t.Fatalf("control queue cap = %d, want %d", got, defaultOutboundControlQueueSize)
@@ -413,8 +413,8 @@ func TestOutboundQueueBackingUsesSmallConfigurableBounds(t *testing.T) {
 		}
 		c.startOutbound()
 		defer c.Close()
-		if got := cap(c.outbound); got != 7 {
-			t.Fatalf("normal queue cap = %d, want 7", got)
+		if got := cap(c.outbound) + cap(c.outboundCritical) + cap(c.outboundBulk); got != 7 {
+			t.Fatalf("ordinary lane total cap = %d, want 7", got)
 		}
 		if got := cap(c.outboundControl); got != 3 {
 			t.Fatalf("control queue cap = %d, want 3", got)
@@ -446,9 +446,11 @@ func TestServerNewConnectionsShareOutboundBudgetAndQueueLimits(t *testing.T) {
 	defer c1.Close()
 	defer c2.Close()
 
-	if cap(c1.outbound) != 7 || cap(c1.outboundControl) != 3 || cap(c2.outbound) != 7 || cap(c2.outboundControl) != 3 {
+	c1Ordinary := cap(c1.outbound) + cap(c1.outboundCritical) + cap(c1.outboundBulk)
+	c2Ordinary := cap(c2.outbound) + cap(c2.outboundCritical) + cap(c2.outboundBulk)
+	if c1Ordinary != 7 || cap(c1.outboundControl) != 3 || c2Ordinary != 7 || cap(c2.outboundControl) != 3 {
 		t.Fatalf("server queue caps = %d/%d and %d/%d, want 7/3",
-			cap(c1.outbound), cap(c1.outboundControl), cap(c2.outbound), cap(c2.outboundControl))
+			c1Ordinary, cap(c1.outboundControl), c2Ordinary, cap(c2.outboundControl))
 	}
 	if c1.outboundTrackedBudget != srv.outboundTrackedBudget || c2.outboundTrackedBudget != srv.outboundTrackedBudget {
 		t.Fatal("server connections did not receive the shared outbound tracking budget")

internal/mtprotoedge/rpc_flight.go

@@ -3,6 +3,7 @@ package mtprotoedge
 import (
 	"context"
 	"errors"
+	"sync"
 	"sync/atomic"
 )
 
@@ -44,9 +45,12 @@ type rpcResultFlight struct {
 	done        chan struct{}
 	encoded     *encodedOutboundMessage
 	ok          bool
+	subscribers []func(*encodedOutboundMessage, bool)
 }
 
 type rpcResultWaiter struct {
+	cache  *rpcResultCache
+	key    rpcResultCacheKey
 	flight *rpcResultFlight
 }
 
@@ -78,10 +82,115 @@ func (w *rpcResultWaiter) Wait(ctx context.Context) (encoded *encodedOutboundMes
 	}
 }
 
+// Subscribe registers an event callback without creating a goroutine or
+// occupying an RPC worker. The callback is invoked after the cache shard lock is
+// released; it must remain non-blocking.
+func (w *rpcResultWaiter) Subscribe(fn func(*encodedOutboundMessage, bool)) error {
+	if w == nil || w.cache == nil || w.flight == nil || fn == nil {
+		return ErrRPCResultFlightInvalid
+	}
+	s := w.cache.shard(w.key)
+	var (
+		encoded *encodedOutboundMessage
+		ok      bool
+		ready   bool
+	)
+	s.mu.Lock()
+	if flight, exists := s.pending[w.key]; exists && flight == w.flight {
+		flight.subscribers = append(flight.subscribers, fn)
+		s.mu.Unlock()
+		return nil
+	}
+	select {
+	case <-w.flight.done:
+		encoded, ok, ready = w.flight.encoded, w.flight.ok, true
+	default:
+	}
+	s.mu.Unlock()
+	if !ready {
+		return ErrRPCResultFlightInvalid
+	}
+	fn(encoded, ok)
+	return nil
+}
+
 type rpcResultOwnerLease struct {
 	cache     *rpcResultCache
 	key       rpcResultCacheKey
 	flight    *rpcResultFlight
+	delivery  *rpcResultDelivery
+	hookMu    sync.Mutex
+	abortHook func()
+	// handedOff means the inbound worker transferred terminal-result ownership to
+	// the bounded egress pipeline. Its ordinary release callback must no longer
+	// abort the flight merely because the socket write is still pending.
+	handedOff atomic.Bool
+}
+
+func (l *rpcResultOwnerLease) SetAbortHook(fn func()) {
+	if l == nil {
+		return
+	}
+	l.hookMu.Lock()
+	l.abortHook = fn
+	l.hookMu.Unlock()
+}
+
+// InstallAbortHook installs fn only while this lease still owns the pending
+// flight. The shard lock linearizes installation with Abort/Put so a registry
+// cannot publish a candidate after its owner has already disappeared.
+func (l *rpcResultOwnerLease) InstallAbortHook(fn func()) bool {
+	if l == nil || l.cache == nil || l.flight == nil || fn == nil {
+		return false
+	}
+	s := l.cache.shard(l.key)
+	s.mu.Lock()
+	flight, ok := s.pending[l.key]
+	if !ok || flight != l.flight {
+		s.mu.Unlock()
+		return false
+	}
+	l.hookMu.Lock()
+	l.abortHook = fn
+	l.hookMu.Unlock()
+	s.mu.Unlock()
+	return true
+}
+
+func (l *rpcResultOwnerLease) Waiter() *rpcResultWaiter {
+	if l == nil || l.cache == nil || l.flight == nil {
+		return nil
+	}
+	return &rpcResultWaiter{cache: l.cache, key: l.key, flight: l.flight}
+}
+
+func (l *rpcResultOwnerLease) TryRetarget(reqMsgID int64) bool {
+	return l != nil && l.delivery != nil && (&encodedOutboundMessage{delivery: l.delivery}).tryRetarget(reqMsgID)
+}
+
+func (l *rpcResultOwnerLease) Delivery() *rpcResultDelivery {
+	if l == nil {
+		return nil
+	}
+	return l.delivery
+}
+
+// HandOff transfers completion responsibility from the inbound RPC task to an
+// already-admitted egress operation. The egress terminal callback must resolve
+// the flight through Put on both successful delivery and fenced failure.
+func (l *rpcResultOwnerLease) HandOff() bool {
+	if l == nil || l.cache == nil || l.flight == nil {
+		return false
+	}
+	s := l.cache.shard(l.key)
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	flight, ok := s.pending[l.key]
+	if !ok || flight != l.flight {
+		return false
+	}
+	l.handedOff.Store(true)
+	return true
 }
 
 // Abort releases an unfinished owner claim and wakes every waiter with no
@@ -91,17 +200,37 @@ func (l *rpcResultOwnerLease) Abort() bool {
 	if l == nil || l.cache == nil || l.flight == nil {
 		return false
 	}
+	if l.handedOff.Load() {
+		return false
+	}
 	s := l.cache.shard(l.key)
 	s.mu.Lock()
-	defer s.mu.Unlock()
+	if l.handedOff.Load() {
+		s.mu.Unlock()
+		return false
+	}
 
 	flight, ok := s.pending[l.key]
 	if !ok || flight != l.flight {
+		s.mu.Unlock()
 		return false
 	}
 	delete(s.pending, l.key)
 	l.cache.flightLimit.release()
+	subscribers := append([]func(*encodedOutboundMessage, bool){}, flight.subscribers...)
+	flight.subscribers = nil
 	close(flight.done)
+	s.mu.Unlock()
+	l.hookMu.Lock()
+	abortHook := l.abortHook
+	l.abortHook = nil
+	l.hookMu.Unlock()
+	if abortHook != nil {
+		abortHook()
+	}
+	for _, subscriber := range subscribers {
+		subscriber(nil, false)
+	}
 	return true
 }
 
@@ -168,7 +297,7 @@ func (c *rpcResultCache) Acquire(authKeyID [8]byte, sessionID, reqMsgID int64) (
 	if flight, ok := s.pending[key]; ok {
 		return rpcResultAcquire{
 			state:  rpcResultAcquirePending,
-			waiter: &rpcResultWaiter{flight: flight},
+			waiter: &rpcResultWaiter{cache: c, key: key, flight: flight},
 		}, nil
 	}
 	if !c.flightLimit.reserve() {
@@ -181,7 +310,9 @@ func (c *rpcResultCache) Acquire(authKeyID [8]byte, sessionID, reqMsgID int64) (
 	s.pending[key] = flight
 	return rpcResultAcquire{
 		state: rpcResultAcquireOwner,
-		owner: &rpcResultOwnerLease{cache: c, key: key, flight: flight},
+		owner: &rpcResultOwnerLease{
+			cache: c, key: key, flight: flight, delivery: newRPCResultDelivery(reqMsgID),
+		},
 	}, nil
 }
 
@@ -191,17 +322,20 @@ func (c *rpcResultCache) completeRPCResultFlightLocked(
 	s *rpcResultCacheShard,
 	key rpcResultCacheKey,
 	encoded *encodedOutboundMessage,
-) {
+) []func(*encodedOutboundMessage, bool) {
 	if c == nil || s == nil || encoded == nil {
-		return
+		return nil
 	}
 	flight, ok := s.pending[key]
 	if !ok {
-		return
+		return nil
 	}
 	delete(s.pending, key)
 	flight.encoded = encoded
 	flight.ok = true
 	c.flightLimit.release()
+	subscribers := append([]func(*encodedOutboundMessage, bool){}, flight.subscribers...)
+	flight.subscribers = nil
 	close(flight.done)
+	return subscribers
 }

internal/mtprotoedge/rpc_result_cache.go

@@ -118,7 +118,6 @@ func (c *rpcResultCache) Put(authKeyID [8]byte, sessionID, reqMsgID int64, encod
 	now := s.now()
 
 	s.mu.Lock()
-	defer s.mu.Unlock()
 
 	if cacheable {
 		s.expireLocked(now)
@@ -139,7 +138,11 @@ func (c *rpcResultCache) Put(authKeyID [8]byte, sessionID, reqMsgID int64, encod
 	// Resolve the independent in-flight entry only after the completed cache has
 	// been published. Waiters awakened by this close can therefore immediately
 	// observe either the shared encoded result or the completed Get entry.
-	c.completeRPCResultFlightLocked(s, key, encoded)
+	subscribers := c.completeRPCResultFlightLocked(s, key, encoded)
+	s.mu.Unlock()
+	for _, subscriber := range subscribers {
+		subscriber(encoded, true)
+	}
 }
 
 func (s *rpcResultCacheShard) expireLocked(now time.Time) {

internal/mtprotoedge/rpc_result_egress.go

@@ -0,0 +1,110 @@
+package mtprotoedge
+
+import (
+	"context"
+	"strings"
+	"sync"
+
+	"github.com/gotd/td/bin"
+	"github.com/gotd/td/proto"
+)
+
+const (
+	rpcResultGZIPMinBytes        = 4 << 10
+	rpcResultGZIPMaxInputBytes   = (10 << 20) - 1 // gotd client decompression hard limit.
+	rpcResultGZIPMinSavedBytes   = 1 << 10
+	rpcResultGZIPMinSavedDivisor = 12 // Require roughly 8.3% reduction.
+	rpcResultGZIPConcurrency     = 8
+	rpcDeliveryHookConcurrency   = 8
+	rpcDeliveryHookQueueSize     = 1024
+)
+
+var rpcResultGZIPSlots = make(chan struct{}, rpcResultGZIPConcurrency)
+
+var (
+	rpcDeliveryHooksOnce sync.Once
+	rpcDeliveryHooks     chan func()
+)
+
+// scheduleRPCDeliveryHook keeps database/update follow-up work off the sole
+// socket writer. Hooks are internal, bounded and timeout-aware at registration
+// sites; the fixed worker set prevents one delivered result from stalling every
+// subsequent frame on that connection.
+func scheduleRPCDeliveryHook(fn func()) {
+	if fn == nil {
+		return
+	}
+	rpcDeliveryHooksOnce.Do(func() {
+		rpcDeliveryHooks = make(chan func(), rpcDeliveryHookQueueSize)
+		for range rpcDeliveryHookConcurrency {
+			go func() {
+				for hook := range rpcDeliveryHooks {
+					hook()
+				}
+			}()
+		}
+	})
+	rpcDeliveryHooks <- fn
+}
+
+// encodeAdaptiveRPCResultInner returns either the original layer-specific TL
+// object or one complete gzip_packed object. Compression is CPU bounded and is
+// retained only when it materially reduces the non-preemptible transport frame.
+func encodeAdaptiveRPCResultInner(ctx context.Context, stop <-chan struct{}, inner []byte) ([]byte, bool, error) {
+	if len(inner) < rpcResultGZIPMinBytes || len(inner) > rpcResultGZIPMaxInputBytes {
+		return inner, false, nil
+	}
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	select {
+	case rpcResultGZIPSlots <- struct{}{}:
+	case <-ctx.Done():
+		return nil, false, ctx.Err()
+	case <-stop:
+		return nil, false, ErrConnClosed
+	}
+	defer func() { <-rpcResultGZIPSlots }()
+
+	var packed bin.Buffer
+	if err := (proto.GZIP{Data: inner}).Encode(&packed); err != nil {
+		return nil, false, err
+	}
+	saved := len(inner) - packed.Len()
+	required := max(rpcResultGZIPMinSavedBytes, len(inner)/rpcResultGZIPMinSavedDivisor)
+	if saved < required {
+		return inner, false, nil
+	}
+	return packed.Raw(), true, nil
+}
+
+// rpcResultPriority is protocol scheduling metadata, not handler business
+// behavior. Difference/state responses converge the update state, while the
+// dialogs+pinned pair converges the initial chat list in both TDesktop and
+// Android. These bootstrap barriers must pass background prefetch regardless of
+// platform or their own encoded size.
+func rpcResultPriority(method string, encoded *encodedOutboundMessage) outboundPriority {
+	base := method
+	if i := strings.IndexByte(base, '#'); i >= 0 {
+		base = base[:i]
+	}
+	switch base {
+	case "updates.getDifference", "updates.getChannelDifference", "updates.getState",
+		"messages.getDialogs", "messages.getPinnedDialogs":
+		return outboundPriorityCritical
+	}
+	return classifyOutboundPriority(encoded, false)
+}
+
+func (p outboundPriority) String() string {
+	switch p {
+	case outboundPriorityCritical:
+		return "convergence"
+	case outboundPriorityBulk:
+		return "bulk"
+	case outboundPriorityControl:
+		return "control"
+	default:
+		return "normal"
+	}
+}

internal/mtprotoedge/rpc_result_egress_test.go

@@ -0,0 +1,444 @@
+package mtprotoedge
+
+import (
+	"bytes"
+	"context"
+	"crypto/rand"
+	"io"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/gotd/td/bin"
+	"github.com/gotd/td/crypto"
+	"github.com/gotd/td/proto"
+	"github.com/gotd/td/tg"
+)
+
+type opaqueRPCResult struct{ body []byte }
+
+func (o opaqueRPCResult) Encode(b *bin.Buffer) error {
+	b.PutID(0x10203040)
+	b.Put(o.body)
+	return nil
+}
+
+func TestEncodeRPCResultUsesAdaptiveGZIP(t *testing.T) {
+	s := New(Options{})
+	c := &Conn{metrics: NopMetrics{}}
+	large := &tg.DataJSON{Data: string(bytes.Repeat([]byte("sticker-metadata-"), 16<<10))}
+	encoded, err := s.encodeRPCResult(c, 123, large)
+	if err != nil {
+		t.Fatalf("encode compressed rpc_result: %v", err)
+	}
+	if !encoded.compressed {
+		t.Fatal("compressible large rpc_result was not gzip_packed")
+	}
+	if encoded.uncompressedBytes <= len(encoded.body) {
+		t.Fatalf("compressed wire=%d is not smaller than inner=%d", len(encoded.body), encoded.uncompressedBytes)
+	}
+	var result proto.Result
+	if err := result.Decode(&bin.Buffer{Buf: encoded.body}); err != nil {
+		t.Fatalf("decode rpc_result: %v", err)
+	}
+	var packed proto.GZIP
+	if err := packed.Decode(&bin.Buffer{Buf: result.Result}); err != nil {
+		t.Fatalf("decode gzip_packed: %v", err)
+	}
+	var decoded tg.DataJSON
+	if err := decoded.Decode(&bin.Buffer{Buf: packed.Data}); err != nil {
+		t.Fatalf("decode compressed inner result: %v", err)
+	}
+	if decoded.Data != large.Data {
+		t.Fatal("gzip round trip changed rpc_result")
+	}
+}
+
+func TestEncodeRPCResultKeepsIncompressibleBodyRaw(t *testing.T) {
+	s := New(Options{})
+	c := &Conn{metrics: NopMetrics{}}
+	raw := make([]byte, 96<<10)
+	if _, err := rand.Read(raw); err != nil {
+		t.Fatalf("random body: %v", err)
+	}
+	encoded, err := s.encodeRPCResult(c, 456, opaqueRPCResult{body: raw})
+	if err != nil {
+		t.Fatalf("encode incompressible rpc_result: %v", err)
+	}
+	if encoded.compressed {
+		t.Fatal("incompressible rpc_result retained a larger gzip envelope")
+	}
+	var result proto.Result
+	if err := result.Decode(&bin.Buffer{Buf: encoded.body}); err != nil {
+		t.Fatalf("decode raw rpc_result: %v", err)
+	}
+	id, err := (&bin.Buffer{Buf: result.Result}).PeekID()
+	if err != nil || id != 0x10203040 {
+		t.Fatalf("raw result type = %#x err=%v", id, err)
+	}
+}
+
+func TestBootstrapBarriersAlwaysUseConvergenceLane(t *testing.T) {
+	large := &encodedOutboundMessage{body: make([]byte, bulkOutboundThreshold)}
+	for _, method := range []string{
+		"updates.getDifference", "updates.getDifference#25939651",
+		"updates.getChannelDifference#03173d78", "updates.getState",
+		"messages.getDialogs", "messages.getDialogs#a0f4cb4f",
+		"messages.getPinnedDialogs", "messages.getPinnedDialogs#d6b94df2",
+	} {
+		if got := rpcResultPriority(method, large); got != outboundPriorityCritical {
+			t.Fatalf("priority(%q) = %s, want convergence", method, got.String())
+		}
+	}
+	if got := rpcResultPriority("messages.getStickerSet", large); got != outboundPriorityBulk {
+		t.Fatalf("sticker-set priority = %s, want bulk", got.String())
+	}
+}
+
+type gatedRecordingTransport struct {
+	started chan struct{}
+	release chan struct{}
+	once    sync.Once
+	sends   atomic.Int32
+	mu      sync.Mutex
+	frames  [][]byte
+}
+
+func newGatedRecordingTransport() *gatedRecordingTransport {
+	return &gatedRecordingTransport{started: make(chan struct{}), release: make(chan struct{})}
+}
+
+func (t *gatedRecordingTransport) Send(_ context.Context, b *bin.Buffer) error {
+	if t.sends.Add(1) == 1 {
+		close(t.started)
+		<-t.release
+	}
+	t.mu.Lock()
+	t.frames = append(t.frames, append([]byte(nil), b.Raw()...))
+	t.mu.Unlock()
+	return nil
+}
+
+func (*gatedRecordingTransport) Recv(context.Context, *bin.Buffer) error { return io.EOF }
+func (t *gatedRecordingTransport) Close() error {
+	t.once.Do(func() { close(t.release) })
+	return nil
+}
+
+func (t *gatedRecordingTransport) snapshot() [][]byte {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	out := make([][]byte, len(t.frames))
+	for i := range t.frames {
+		out[i] = append([]byte(nil), t.frames[i]...)
+	}
+	return out
+}
+
+func encodedRPCResultForPriorityTest(reqMsgID int64, payloadBytes int) *encodedOutboundMessage {
+	var b bin.Buffer
+	b.PutID(proto.ResultTypeID)
+	b.PutLong(reqMsgID)
+	b.PutID(tg.BoolTrueTypeID)
+	if payloadBytes > 0 {
+		b.Put(make([]byte, payloadBytes))
+	}
+	return &encodedOutboundMessage{typeID: proto.ResultTypeID, reqMsgID: reqMsgID, body: b.Raw()}
+}
+
+func TestConvergenceResultPassesQueuedBulkAfterBlockedWrite(t *testing.T) {
+	tr := newGatedRecordingTransport()
+	c := newOutboundTestConn(t, tr, newOutboundTrackedBudget(2<<20))
+	gate := &encodedOutboundMessage{typeID: tg.UpdatesTooLongTypeID, body: []byte{0x0b, 0xa1, 0x01, 0xe3}}
+	if err := c.SendBestEffortEncoded(context.Background(), proto.MessageFromServer, gate, 0); err != nil {
+		t.Fatalf("enqueue gate: %v", err)
+	}
+	select {
+	case <-tr.started:
+	case <-time.After(time.Second):
+		t.Fatal("first write did not block")
+	}
+
+	const ordinaryResults = 17
+	for i := 0; i < ordinaryResults; i++ {
+		ordinary := encodedRPCResultForPriorityTest(2000+int64(i), 0)
+		if err := c.enqueueEncodedDelivery(context.Background(), proto.MessageServerResponse, ordinary, outboundPriorityNormal, nil); err != nil {
+			t.Fatalf("enqueue ordinary result %d: %v", i, err)
+		}
+	}
+	bulk := encodedRPCResultForPriorityTest(1001, bulkOutboundThreshold)
+	critical := encodedRPCResultForPriorityTest(1002, 0)
+	if err := c.enqueueEncodedDelivery(context.Background(), proto.MessageServerResponse, bulk, outboundPriorityBulk, nil); err != nil {
+		t.Fatalf("enqueue bulk: %v", err)
+	}
+	if err := c.enqueueEncodedDelivery(context.Background(), proto.MessageServerResponse, critical, outboundPriorityCritical, nil); err != nil {
+		t.Fatalf("enqueue convergence result: %v", err)
+	}
+	tr.once.Do(func() { close(tr.release) })
+	wantSends := int32(1 + ordinaryResults + 2)
+	deadline := time.Now().Add(2 * time.Second)
+	for tr.sends.Load() < wantSends && time.Now().Before(deadline) {
+		time.Sleep(time.Millisecond)
+	}
+	if got := tr.sends.Load(); got != wantSends {
+		t.Fatalf("physical sends = %d, want %d", got, wantSends)
+	}
+
+	var resultOrder []int64
+	clientCipher := crypto.NewClientCipher(rand.Reader)
+	for _, frame := range tr.snapshot() {
+		data, err := clientCipher.DecryptFromBuffer(c.key, &bin.Buffer{Buf: frame})
+		if err != nil {
+			t.Fatalf("decrypt frame: %v", err)
+		}
+		plain := &bin.Buffer{Buf: append([]byte(nil), data.Data()...)}
+		id, err := plain.PeekID()
+		if err != nil || id != proto.ResultTypeID {
+			continue
+		}
+		var result proto.Result
+		if err := result.Decode(plain); err != nil {
+			t.Fatalf("decode result: %v", err)
+		}
+		resultOrder = append(resultOrder, result.RequestMessageID)
+	}
+	if len(resultOrder) != ordinaryResults+2 || resultOrder[0] != 1002 {
+		t.Fatalf("rpc_result order = %v, want convergence first", resultOrder)
+	}
+	bulkIndex := -1
+	for i, reqMsgID := range resultOrder {
+		if reqMsgID == 1001 {
+			bulkIndex = i
+			break
+		}
+	}
+	if bulkIndex < 0 || bulkIndex > maxOrdinaryBeforeBulk+1 {
+		t.Fatalf("bulk result index = %d in %v, want bounded ordinary burst", bulkIndex, resultOrder)
+	}
+}
+
+type immediateLargeRPC struct{}
+
+func (immediateLargeRPC) Dispatch(context.Context, [8]byte, int64, *bin.Buffer) (bin.Encoder, error) {
+	return &tg.DataJSON{Data: string(bytes.Repeat([]byte("large-sticker-set"), 16<<10))}, nil
+}
+
+func (immediateLargeRPC) NegotiatedLayer([8]byte, int64) (int, bool) { return 227, true }
+
+type wrappedConvergenceRPC struct{ immediateLargeRPC }
+
+func (w wrappedConvergenceRPC) DispatchWithMethod(
+	ctx context.Context,
+	authKeyID [8]byte,
+	sessionID int64,
+	b *bin.Buffer,
+) (bin.Encoder, string, error) {
+	result, err := w.Dispatch(ctx, authKeyID, sessionID, b)
+	return result, "updates.getDifference", err
+}
+
+type captureRPCResultMetrics struct {
+	NopMetrics
+	mu             sync.Mutex
+	preparedMethod string
+	priority       string
+	innerBytes     int
+	wireBytes      int
+	compressed     bool
+	delivered      chan error
+}
+
+func (m *captureRPCResultMetrics) RPCResultPrepared(method, priority string, innerBytes, wireBytes int, compressed bool) {
+	m.mu.Lock()
+	m.preparedMethod, m.priority = method, priority
+	m.innerBytes, m.wireBytes, m.compressed = innerBytes, wireBytes, compressed
+	m.mu.Unlock()
+}
+
+func (m *captureRPCResultMetrics) RPCResultDelivered(_ string, _ time.Duration, _ int, err error) {
+	m.delivered <- err
+}
+
+func TestRPCResultPipelineExportsPreparationAndDeliveryMetrics(t *testing.T) {
+	metrics := &captureRPCResultMetrics{delivered: make(chan error, 1)}
+	s := New(Options{Metrics: metrics})
+	c := newOutboundTestConn(t, &failAfterTransport{}, newOutboundTrackedBudget(1<<20))
+	const reqMsgID = int64(9050)
+	claim, err := s.rpcResults.Acquire(c.authKeyID, c.sessionID, reqMsgID)
+	if err != nil || claim.state != rpcResultAcquireOwner {
+		t.Fatalf("acquire flight = %+v err=%v", claim, err)
+	}
+	result := &tg.DataJSON{Data: string(bytes.Repeat([]byte("sticker-data"), 12<<10))}
+	if err := s.publishRPCResult(c, reqMsgID, "updates.getDifference#25939651", claim.owner, result, nil); err != nil {
+		t.Fatalf("publish result: %v", err)
+	}
+	select {
+	case err := <-metrics.delivered:
+		if err != nil {
+			t.Fatalf("delivery metric error: %v", err)
+		}
+	case <-time.After(time.Second):
+		t.Fatal("missing delivery metric")
+	}
+	metrics.mu.Lock()
+	defer metrics.mu.Unlock()
+	if metrics.preparedMethod != "updates.getDifference#25939651" || metrics.priority != "convergence" {
+		t.Fatalf("prepared metric = %q/%q", metrics.preparedMethod, metrics.priority)
+	}
+	if !metrics.compressed || metrics.innerBytes <= metrics.wireBytes {
+		t.Fatalf("compression metric = compressed:%v inner:%d wire:%d", metrics.compressed, metrics.innerBytes, metrics.wireBytes)
+	}
+}
+
+func TestWrappedConvergenceMethodDrivesEgressAndReplayPriority(t *testing.T) {
+	metrics := &captureRPCResultMetrics{delivered: make(chan error, 1)}
+	s := New(Options{RPC: wrappedConvergenceRPC{}, Metrics: metrics})
+	c := newOutboundTestConn(t, &failAfterTransport{}, newOutboundTrackedBudget(1<<20))
+	const reqMsgID = int64(9051)
+	claim, err := s.rpcResults.Acquire(c.authKeyID, c.sessionID, reqMsgID)
+	if err != nil || claim.state != rpcResultAcquireOwner {
+		t.Fatalf("acquire flight = %+v err=%v", claim, err)
+	}
+	body := mustEncodeTL(t, &tg.HelpGetConfigRequest{})
+	if err := s.handleRPC(context.Background(), c, reqMsgID, "invokeWithLayer#da9b0d0d", &bin.Buffer{Buf: body}, claim.owner); err != nil {
+		t.Fatalf("handle wrapped convergence RPC: %v", err)
+	}
+	select {
+	case err := <-metrics.delivered:
+		if err != nil {
+			t.Fatalf("delivery metric error: %v", err)
+		}
+	case <-time.After(time.Second):
+		t.Fatal("missing delivery metric")
+	}
+	metrics.mu.Lock()
+	method, priority := metrics.preparedMethod, metrics.priority
+	metrics.mu.Unlock()
+	if method != "updates.getDifference" || priority != "convergence" {
+		t.Fatalf("wrapped prepared metric = %q/%q, want updates.getDifference/convergence", method, priority)
+	}
+	var cached *encodedOutboundMessage
+	deadline := time.Now().Add(time.Second)
+	for time.Now().Before(deadline) {
+		if got, ok := s.rpcResults.Get(c.authKeyID, c.sessionID, reqMsgID); ok {
+			cached = got
+			break
+		}
+		time.Sleep(time.Millisecond)
+	}
+	if cached == nil {
+		t.Fatal("wrapped convergence result missing from replay cache")
+	}
+	if got := classifyOutboundPriority(cached, false); got != outboundPriorityCritical {
+		t.Fatalf("cached convergence priority = %s, want convergence", got.String())
+	}
+}
+
+func TestRPCWorkerReleasesAfterEgressAdmissionWhileWriteBlocked(t *testing.T) {
+	s := New(Options{RPC: immediateLargeRPC{}, WriteTimeout: time.Second})
+	tr := newGatedRecordingTransport()
+	c := newOutboundTestConn(t, tr, newOutboundTrackedBudget(2<<20))
+	const reqMsgID = int64(9001)
+	claim, err := s.rpcResults.Acquire(c.authKeyID, c.sessionID, reqMsgID)
+	if err != nil || claim.state != rpcResultAcquireOwner {
+		t.Fatalf("acquire flight = %+v err=%v", claim, err)
+	}
+	body := mustEncodeTL(t, &tg.HelpGetConfigRequest{})
+	task := s.newInboundRPCTask(c, reqMsgID, "updates.getDifference#25939651", body, claim.owner)
+	done := make(chan error, 1)
+	go func() { done <- task.run(context.Background()) }()
+	select {
+	case <-tr.started:
+	case <-time.After(time.Second):
+		t.Fatal("rpc_result write did not start")
+	}
+	select {
+	case err := <-done:
+		if err != nil {
+			t.Fatalf("RPC worker result: %v", err)
+		}
+	case <-time.After(250 * time.Millisecond):
+		t.Fatal("RPC worker remained coupled to blocked physical write")
+	}
+	acquired, err := s.rpcResults.Acquire(c.authKeyID, c.sessionID, reqMsgID)
+	if err != nil || acquired.state != rpcResultAcquirePending {
+		t.Fatalf("blocked delivery flight = %+v err=%v, want pending", acquired, err)
+	}
+	if task.release != nil {
+		task.release()
+	}
+	if claim.owner.Abort() {
+		t.Fatal("detached egress flight was aborted by inbound release")
+	}
+	tr.once.Do(func() { close(tr.release) })
+	deadline := time.Now().Add(time.Second)
+	for {
+		if _, ok := s.rpcResults.Get(c.authKeyID, c.sessionID, reqMsgID); ok {
+			break
+		}
+		if time.Now().After(deadline) {
+			t.Fatal("delivered result was not published to replay cache")
+		}
+		time.Sleep(time.Millisecond)
+	}
+}
+
+func TestDeliveryHookRunsOnceAfterReplayNotFailedWrite(t *testing.T) {
+	s := New(Options{})
+	failing := &failAfterTransport{}
+	failing.failAt.Store(1)
+	oldConn := newOutboundTestConn(t, failing, newOutboundTrackedBudget(1<<20))
+	const reqMsgID = int64(9101)
+	claim, err := s.rpcResults.Acquire(oldConn.authKeyID, oldConn.sessionID, reqMsgID)
+	if err != nil || claim.state != rpcResultAcquireOwner {
+		t.Fatalf("acquire flight = %+v err=%v", claim, err)
+	}
+	var hooks atomic.Int32
+	if err := s.publishRPCResult(oldConn, reqMsgID, "updates.getDifference", claim.owner,
+		&tg.DataJSON{Data: "difference"}, func() { hooks.Add(1) }); err != nil {
+		// Admission succeeds; the asynchronous physical failure is observed below.
+		t.Fatalf("publish result: %v", err)
+	}
+	deadline := time.Now().Add(time.Second)
+	var cached *encodedOutboundMessage
+	for time.Now().Before(deadline) {
+		if got, ok := s.rpcResults.Get(oldConn.authKeyID, oldConn.sessionID, reqMsgID); ok {
+			cached = got
+			break
+		}
+		time.Sleep(time.Millisecond)
+	}
+	if cached == nil {
+		t.Fatal("failed write was not fenced and published for replay")
+	}
+	if got := cached.deliveryState(); got != rpcResultDeliveryReplayable {
+		t.Fatalf("failed delivery state = %d, want replayable", got)
+	}
+	if got := hooks.Load(); got != 0 {
+		t.Fatalf("delivery hooks after failed write = %d, want 0", got)
+	}
+
+	replayTransport := &failAfterTransport{}
+	replayConn := newOutboundTestConn(t, replayTransport, newOutboundTrackedBudget(1<<20))
+	if err := s.sendCachedRPCResult(context.Background(), replayConn, cached); err != nil {
+		t.Fatalf("replay result: %v", err)
+	}
+	deadline = time.Now().Add(time.Second)
+	for hooks.Load() != 1 && time.Now().Before(deadline) {
+		time.Sleep(time.Millisecond)
+	}
+	if got := hooks.Load(); got != 1 {
+		t.Fatalf("delivery hooks after replay = %d, want 1", got)
+	}
+	if got := cached.deliveryState(); got != rpcResultDeliveryDelivered {
+		t.Fatalf("replayed delivery state = %d, want delivered", got)
+	}
+	if err := s.sendCachedRPCResult(context.Background(), replayConn, cached); err != nil {
+		t.Fatalf("second replay: %v", err)
+	}
+	time.Sleep(20 * time.Millisecond)
+	if got := hooks.Load(); got != 1 {
+		t.Fatalf("delivery hooks after duplicate replay = %d, want 1", got)
+	}
+}

internal/mtprotoedge/rpc_rewrap.go

@@ -0,0 +1,455 @@
+package mtprotoedge
+
+import (
+	"context"
+	"crypto/sha256"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"go.uber.org/zap"
+
+	"github.com/gotd/td/bin"
+	"github.com/gotd/td/proto"
+	"github.com/gotd/td/tg"
+)
+
+// rpcRewrapRegistry links only an explicit official-client transition:
+// outstanding naked request -> invokeWithLayer(initConnection(the exact same
+// request)). It is not a general content-dedup cache. Entries are hard-bounded
+// and are retired by protocol events (client ACK, alias consumption, owner
+// abort, or the first post-init naked request), never by client identity or by
+// delaying request execution.
+type rpcRewrapRegistry struct {
+	mu        sync.Mutex
+	max       int
+	total     int
+	byKey     map[rpcRewrapKey][]*rpcRewrapCandidate
+	bySession map[rpcRewrapSessionKey]map[*rpcRewrapCandidate]struct{}
+	byRequest map[rpcRewrapRequestKey]*rpcRewrapCandidate
+}
+
+type rpcRewrapSessionKey struct {
+	authKeyID [8]byte
+	sessionID int64
+}
+
+type rpcRewrapKey struct {
+	rpcRewrapSessionKey
+	fingerprint [sha256.Size]byte
+}
+
+type rpcRewrapRequestKey struct {
+	rpcRewrapSessionKey
+	reqMsgID int64
+}
+
+type rpcRewrapCandidate struct {
+	active   bool
+	claimed  bool
+	key      rpcRewrapKey
+	source   *Conn
+	reqMsgID int64
+	method   string
+	owner    *rpcResultOwnerLease
+	waiter   *rpcResultWaiter
+}
+
+func newRPCRewrapRegistry(max int) *rpcRewrapRegistry {
+	if max <= 0 {
+		max = rpcResultFlightDefaultMaxPending
+	}
+	return &rpcRewrapRegistry{
+		max:       max,
+		byKey:     make(map[rpcRewrapKey][]*rpcRewrapCandidate),
+		bySession: make(map[rpcRewrapSessionKey]map[*rpcRewrapCandidate]struct{}),
+		byRequest: make(map[rpcRewrapRequestKey]*rpcRewrapCandidate),
+	}
+}
+
+func (r *rpcRewrapRegistry) register(c *Conn, body []byte, reqMsgID int64, method string, owner *rpcResultOwnerLease) bool {
+	if r == nil || c == nil || c.rpcRewrapInitialized.Load() || owner == nil {
+		return false
+	}
+	session := rpcRewrapSessionKey{authKeyID: c.authKeyID, sessionID: c.sessionID}
+	key := rpcRewrapKey{rpcRewrapSessionKey: session, fingerprint: sha256.Sum256(body)}
+	candidate := &rpcRewrapCandidate{
+		active: true, key: key, source: c, reqMsgID: reqMsgID, method: method,
+		owner: owner, waiter: owner.Waiter(),
+	}
+	if candidate.waiter == nil {
+		return false
+	}
+	r.mu.Lock()
+	if r.total >= r.max {
+		r.mu.Unlock()
+		return false
+	}
+	r.byKey[key] = append(r.byKey[key], candidate)
+	set := r.bySession[session]
+	if set == nil {
+		set = make(map[*rpcRewrapCandidate]struct{})
+		r.bySession[session] = set
+	}
+	set[candidate] = struct{}{}
+	r.byRequest[rpcRewrapRequestKey{rpcRewrapSessionKey: session, reqMsgID: reqMsgID}] = candidate
+	r.total++
+	r.mu.Unlock()
+	if !owner.InstallAbortHook(func() { r.remove(candidate) }) {
+		r.remove(candidate)
+		return false
+	}
+	return true
+}
+
+func (r *rpcRewrapRegistry) claim(c *Conn, inner []byte) *rpcRewrapCandidate {
+	if r == nil || c == nil {
+		return nil
+	}
+	session := rpcRewrapSessionKey{authKeyID: c.authKeyID, sessionID: c.sessionID}
+	key := rpcRewrapKey{rpcRewrapSessionKey: session, fingerprint: sha256.Sum256(inner)}
+	r.mu.Lock()
+	queue := r.byKey[key]
+	for _, candidate := range queue {
+		if !candidate.active || candidate.claimed {
+			continue
+		}
+		candidate.claimed = true
+		r.mu.Unlock()
+		return candidate
+	}
+	r.mu.Unlock()
+	return nil
+}
+
+func (r *rpcRewrapRegistry) commit(candidate *rpcRewrapCandidate) {
+	if r == nil || candidate == nil {
+		return
+	}
+	r.mu.Lock()
+	r.removeLocked(candidate)
+	r.mu.Unlock()
+	candidate.owner.SetAbortHook(nil)
+}
+
+func (r *rpcRewrapRegistry) release(candidate *rpcRewrapCandidate) {
+	if r == nil || candidate == nil {
+		return
+	}
+	r.mu.Lock()
+	if candidate.active {
+		candidate.claimed = false
+	}
+	r.mu.Unlock()
+}
+
+func (r *rpcRewrapRegistry) remove(candidate *rpcRewrapCandidate) {
+	if r == nil || candidate == nil {
+		return
+	}
+	r.mu.Lock()
+	r.removeLocked(candidate)
+	r.mu.Unlock()
+}
+
+// acknowledge retires a candidate only after the client explicitly ACKs the
+// physical rpc_result. A successful socket write alone is insufficient proof:
+// the client may already have reassigned the request to a new msg_id without
+// parsing that old result.
+func (r *rpcRewrapRegistry) acknowledge(c *Conn, reqMsgID int64) {
+	if r == nil || c == nil || reqMsgID == 0 {
+		return
+	}
+	request := rpcRewrapRequestKey{
+		rpcRewrapSessionKey: rpcRewrapSessionKey{authKeyID: c.authKeyID, sessionID: c.sessionID},
+		reqMsgID:            reqMsgID,
+	}
+	r.mu.Lock()
+	candidate := r.byRequest[request]
+	r.removeLocked(candidate)
+	r.mu.Unlock()
+	if candidate != nil {
+		candidate.owner.SetAbortHook(nil)
+	}
+}
+
+func (r *rpcRewrapRegistry) removeLocked(candidate *rpcRewrapCandidate) {
+	if candidate == nil || !candidate.active {
+		return
+	}
+	candidate.active = false
+	candidate.claimed = false
+	r.total--
+	session := candidate.key.rpcRewrapSessionKey
+	delete(r.byRequest, rpcRewrapRequestKey{rpcRewrapSessionKey: session, reqMsgID: candidate.reqMsgID})
+	if set := r.bySession[session]; set != nil {
+		delete(set, candidate)
+		if len(set) == 0 {
+			delete(r.bySession, session)
+		}
+	}
+	queue := r.byKey[candidate.key]
+	for i, existing := range queue {
+		if existing != candidate {
+			continue
+		}
+		copy(queue[i:], queue[i+1:])
+		queue[len(queue)-1] = nil
+		queue = queue[:len(queue)-1]
+		break
+	}
+	if len(queue) == 0 {
+		delete(r.byKey, candidate.key)
+	} else {
+		r.byKey[candidate.key] = queue
+	}
+}
+
+func (r *rpcRewrapRegistry) clearSession(c *Conn) {
+	if r == nil || c == nil {
+		return
+	}
+	session := rpcRewrapSessionKey{authKeyID: c.authKeyID, sessionID: c.sessionID}
+	r.mu.Lock()
+	set := r.bySession[session]
+	owners := make([]*rpcResultOwnerLease, 0, len(set))
+	for candidate := range set {
+		owners = append(owners, candidate.owner)
+		r.removeLocked(candidate)
+	}
+	r.mu.Unlock()
+	for _, owner := range owners {
+		owner.SetAbortHook(nil)
+	}
+}
+
+type rpcRewrapInit struct {
+	layer       int
+	apiID       int
+	deviceModel string
+	system      string
+	appVersion  string
+	systemLang  string
+	langPack    string
+	langCode    string
+	inner       []byte
+}
+
+type rpcRewrapRawObject struct {
+	data []byte
+}
+
+func (o *rpcRewrapRawObject) Decode(b *bin.Buffer) error {
+	if _, err := b.PeekID(); err != nil {
+		return err
+	}
+	o.data = b.Buf
+	b.Skip(len(b.Buf))
+	return nil
+}
+
+func (o *rpcRewrapRawObject) Encode(b *bin.Buffer) error {
+	b.Put(o.data)
+	return nil
+}
+
+func decodeRPCRewrapInit(body []byte) (rpcRewrapInit, bool) {
+	b := &bin.Buffer{Buf: body}
+	if err := b.ConsumeID(tg.InvokeWithLayerRequestTypeID); err != nil {
+		return rpcRewrapInit{}, false
+	}
+	layer, err := b.Int()
+	if err != nil || layer <= 0 {
+		return rpcRewrapInit{}, false
+	}
+	raw := &rpcRewrapRawObject{}
+	req := tg.InitConnectionRequest{Query: raw}
+	if err := req.Decode(b); err != nil || b.Len() != 0 || len(raw.data) < bin.Word {
+		return rpcRewrapInit{}, false
+	}
+	return rpcRewrapInit{
+		layer: layer, apiID: req.APIID, deviceModel: req.DeviceModel,
+		system: req.SystemVersion, appVersion: req.AppVersion,
+		systemLang: req.SystemLangCode, langPack: req.LangPack, langCode: req.LangCode,
+		inner: raw.data,
+	}, true
+}
+
+type rpcRewrapAlias struct {
+	conn        *Conn
+	newReqID    int64
+	method      string
+	oldWaiter   *rpcResultWaiter
+	newOwner    *rpcResultOwnerLease
+	sourceConn  *Conn
+	sourceOwner *rpcResultOwnerLease
+	retargeted  atomic.Bool
+	observeInit bool
+	init        rpcRewrapInit
+	candidate   *rpcRewrapCandidate
+	registry    *rpcRewrapRegistry
+}
+
+var (
+	rpcRewrapDeliveryOnce sync.Once
+	rpcRewrapDeliveryJobs chan func()
+)
+
+const (
+	rpcRewrapDeliveryWorkers = 4
+	rpcRewrapDeliveryQueue   = 256
+)
+
+func scheduleRPCRewrapDelivery(fn func()) bool {
+	if fn == nil {
+		return false
+	}
+	rpcRewrapDeliveryOnce.Do(func() {
+		rpcRewrapDeliveryJobs = make(chan func(), rpcRewrapDeliveryQueue)
+		for range rpcRewrapDeliveryWorkers {
+			go func() {
+				for job := range rpcRewrapDeliveryJobs {
+					job()
+				}
+			}()
+		}
+	})
+	select {
+	case rpcRewrapDeliveryJobs <- fn:
+		return true
+	default:
+		return false
+	}
+}
+
+func (a *rpcRewrapAlias) activate(s *Server) error {
+	if a == nil || s == nil || a.conn == nil || a.oldWaiter == nil {
+		return ErrRPCResultFlightInvalid
+	}
+	err := a.oldWaiter.Subscribe(func(encoded *encodedOutboundMessage, ok bool) {
+		if !ok || encoded == nil {
+			if a.newOwner != nil {
+				a.newOwner.Abort()
+			}
+			a.conn.fenceUndeliveredRPCResult()
+			return
+		}
+		if a.newOwner == nil {
+			if !scheduleRPCRewrapDelivery(func() {
+				ctx, cancel := context.WithTimeout(context.Background(), min(5*time.Second, max(time.Second, a.conn.writeTimeout)))
+				defer cancel()
+				if err := s.sendCachedRPCResult(ctx, a.conn, encoded); err != nil && !isClientDisconnect(err) {
+					s.log.Debug("RPC init rewrap pending replay failed", zap.Error(err))
+				}
+			}) {
+				a.conn.fenceUndeliveredRPCResult()
+			}
+			return
+		}
+		clone, err := cloneRPCResultForRequest(encoded, a.newReqID, false)
+		if err != nil {
+			a.newOwner.Abort()
+			a.conn.fenceUndeliveredRPCResult()
+			return
+		}
+		if a.retargeted.Load() {
+			if !a.newOwner.HandOff() {
+				a.conn.fenceUndeliveredRPCResult()
+				return
+			}
+			clone.markDelivered()
+			s.storeRPCResult(a.conn, a.newReqID, clone)
+			s.log.Info("RPC init rewrap result retargeted",
+				zap.String("method", a.method), zap.Int64("new_req_msg_id", a.newReqID),
+				zap.String("auth_key_id", a.conn.authKeyHex), zap.Int64("session_id", a.conn.sessionID))
+			return
+		}
+		if !scheduleRPCRewrapDelivery(func() {
+			s.publishRewrappedRPCResult(a.conn, a.newReqID, a.method, a.newOwner, clone)
+		}) {
+			// The completed result is durable in memory. Fence before publishing it
+			// under the new msg_id so a replacement can replay without re-executing.
+			a.conn.fenceUndeliveredRPCResult()
+			if a.newOwner.HandOff() {
+				clone.markReplayable()
+				s.storeRPCResult(a.conn, a.newReqID, clone)
+			}
+		}
+	})
+	if err != nil {
+		s.rpcRewrap.release(a.candidate)
+		return err
+	}
+	// Subscribe first so every terminal owner event has a consumer. If completion
+	// wins this race the callback replays under the new ID; if retarget wins, the
+	// sole outbound actor snapshots the new ID before writing.
+	if a.newOwner != nil && a.sourceConn == a.conn && a.sourceOwner != nil {
+		a.retargeted.Store(a.sourceOwner.TryRetarget(a.newReqID))
+	}
+	if a.observeInit {
+		s.scheduleRewrappedInitObservation(a.conn, a.init)
+	}
+	s.rpcRewrap.commit(a.candidate)
+	a.candidate = nil
+	return nil
+}
+
+func (a *rpcRewrapAlias) releaseCandidate() {
+	if a == nil || a.candidate == nil {
+		return
+	}
+	a.registry.release(a.candidate)
+	a.candidate = nil
+}
+
+func (s *Server) scheduleRewrappedInitObservation(c *Conn, init rpcRewrapInit) {
+	observer, ok := s.rpc.(RPCInitConnectionObserver)
+	if !ok || c == nil {
+		return
+	}
+	if !scheduleRPCRewrapDelivery(func() {
+		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		defer cancel()
+		if err := observer.ObserveInitConnection(
+			ctx, c.authKeyID, c.sessionID, init.layer, init.apiID,
+			init.deviceModel, init.system, init.appVersion, init.systemLang,
+			init.langPack, init.langCode,
+		); err != nil {
+			s.log.Debug("Observe rewrapped initConnection failed", zap.Error(err))
+		}
+	}) {
+		s.log.Debug("Observe rewrapped initConnection dropped", zap.String("auth_key_id", c.authKeyHex))
+	}
+}
+
+func (s *Server) publishRewrappedRPCResult(c *Conn, reqMsgID int64, method string, owner *rpcResultOwnerLease, encoded *encodedOutboundMessage) {
+	if s == nil || c == nil || owner == nil || encoded == nil {
+		return
+	}
+	if !owner.HandOff() {
+		c.fenceUndeliveredRPCResult()
+		return
+	}
+	priority := rpcResultPriority(method, encoded)
+	encoded.priority = priority
+	terminal := func(deliveryErr error) {
+		if deliveryErr != nil {
+			encoded.markReplayable()
+			c.fenceUndeliveredRPCResult()
+		} else {
+			encoded.markDelivered()
+		}
+		s.storeRPCResult(c, reqMsgID, encoded)
+	}
+	encoded.markQueued()
+	ctx, cancel := context.WithTimeout(context.Background(), min(5*time.Second, max(time.Second, c.writeTimeout)))
+	defer cancel()
+	if err := c.enqueueEncodedDelivery(ctx, proto.MessageServerResponse, encoded, priority, terminal); err != nil {
+		terminal(err)
+		return
+	}
+	s.log.Info("RPC init rewrap result replay admitted",
+		zap.String("method", method), zap.Int64("req_msg_id", reqMsgID),
+		zap.String("auth_key_id", c.authKeyHex), zap.Int64("session_id", c.sessionID),
+		zap.Int("wire_bytes", len(encoded.body)))
+}

internal/mtprotoedge/rpc_rewrap_test.go

@@ -0,0 +1,299 @@
+package mtprotoedge
+
+import (
+	"context"
+	"encoding/binary"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/gotd/td/bin"
+	"github.com/gotd/td/crypto"
+	"github.com/gotd/td/mt"
+	"github.com/gotd/td/tg"
+)
+
+func encodeRewrapTestRequest(t *testing.T) ([]byte, []byte) {
+	t.Helper()
+	var inner bin.Buffer
+	if err := (&tg.HelpGetConfigRequest{}).Encode(&inner); err != nil {
+		t.Fatalf("encode inner request: %v", err)
+	}
+	var wrapped bin.Buffer
+	if err := (&tg.InvokeWithLayerRequest{
+		Layer: 227,
+		Query: &tg.InitConnectionRequest{
+			APIID: 6, DeviceModel: "Pixel", SystemVersion: "SDK 36",
+			AppVersion: "12.8.1", SystemLangCode: "en", LangPack: "android", LangCode: "en",
+			Query: &tg.HelpGetConfigRequest{},
+		},
+	}).Encode(&wrapped); err != nil {
+		t.Fatalf("encode wrapped request: %v", err)
+	}
+	return append([]byte(nil), inner.Raw()...), append([]byte(nil), wrapped.Raw()...)
+}
+
+func TestDecodeRPCRewrapInitExtractsExactInnerQuery(t *testing.T) {
+	inner, wrapped := encodeRewrapTestRequest(t)
+	init, ok := decodeRPCRewrapInit(wrapped)
+	if !ok {
+		t.Fatal("valid invokeWithLayer(initConnection(query)) was not recognized")
+	}
+	if init.layer != 227 || init.apiID != 6 || init.langPack != "android" {
+		t.Fatalf("metadata = layer:%d api:%d lang_pack:%q", init.layer, init.apiID, init.langPack)
+	}
+	if string(init.inner) != string(inner) {
+		t.Fatalf("inner = %x, want %x", init.inner, inner)
+	}
+	if _, ok := decodeRPCRewrapInit(inner); ok {
+		t.Fatal("naked request must not be classified as an init rewrap")
+	}
+}
+
+func TestRPCResultDeliveryRetargetHasExactWritingBarrier(t *testing.T) {
+	const oldReqID, newReqID, tooLateReqID = int64(101), int64(202), int64(303)
+	encoded := &encodedOutboundMessage{
+		typeID: mt.RPCResultTypeID, reqMsgID: oldReqID,
+		body: make([]byte, 16), delivery: newRPCResultDelivery(oldReqID),
+	}
+	if !encoded.tryRetarget(newReqID) {
+		t.Fatal("prepared result should be retargetable")
+	}
+	if got := encoded.beginWriting(); got != newReqID {
+		t.Fatalf("writing target = %d, want %d", got, newReqID)
+	}
+	if encoded.tryRetarget(tooLateReqID) {
+		t.Fatal("writing result must not be mutated")
+	}
+}
+
+func TestRPCResultWaiterSubscribeIsEventDriven(t *testing.T) {
+	cache := newRPCResultCacheWithFlightLimit(time.Now, 8)
+	claim, err := cache.Acquire([8]byte{1}, 2, 3)
+	if err != nil || claim.state != rpcResultAcquireOwner {
+		t.Fatalf("Acquire owner = %+v, %v", claim, err)
+	}
+	var called atomic.Bool
+	if err := claim.owner.Waiter().Subscribe(func(encoded *encodedOutboundMessage, ok bool) {
+		if !ok || encoded == nil {
+			t.Errorf("subscriber result = %#v, %v", encoded, ok)
+		}
+		called.Store(true)
+	}); err != nil {
+		t.Fatalf("Subscribe: %v", err)
+	}
+	if called.Load() {
+		t.Fatal("Subscribe waited for or fabricated a result")
+	}
+	encoded := &encodedOutboundMessage{typeID: mt.RPCResultTypeID, body: make([]byte, 16), reqMsgID: 3}
+	cache.Put([8]byte{1}, 2, 3, encoded)
+	if !called.Load() {
+		t.Fatal("completion event did not invoke subscriber")
+	}
+}
+
+func TestRPCResultOwnerAbortHookInstallationIsFlightBound(t *testing.T) {
+	cache := newRPCResultCacheWithFlightLimit(time.Now, 8)
+	claim, err := cache.Acquire([8]byte{2}, 3, 4)
+	if err != nil || claim.state != rpcResultAcquireOwner {
+		t.Fatalf("Acquire owner = %+v, %v", claim, err)
+	}
+	var called atomic.Bool
+	if !claim.owner.InstallAbortHook(func() { called.Store(true) }) {
+		t.Fatal("live owner rejected abort hook")
+	}
+	if !claim.owner.Abort() || !called.Load() {
+		t.Fatal("owner abort did not invoke installed hook")
+	}
+	if claim.owner.InstallAbortHook(func() {}) {
+		t.Fatal("completed flight accepted a new abort hook")
+	}
+}
+
+func TestRPCRewrapRegistryIsPlatformAgnosticAndAckBound(t *testing.T) {
+	cache := newRPCResultCacheWithFlightLimit(time.Now, 8)
+	claim, err := cache.Acquire([8]byte{4}, 5, 6)
+	if err != nil || claim.state != rpcResultAcquireOwner {
+		t.Fatalf("Acquire owner = %+v, %v", claim, err)
+	}
+	c := &Conn{authKeyID: [8]byte{4}, sessionID: 5}
+	r := newRPCRewrapRegistry(8)
+	body := []byte{1, 2, 3, 4}
+	if !r.register(c, body, 6, "test.method", claim.owner) {
+		t.Fatal("protocol candidate was rejected without platform metadata")
+	}
+	candidate := r.claim(c, body)
+	if candidate == nil {
+		t.Fatal("exact protocol fingerprint did not match")
+	}
+	if got := r.claim(c, body); got != nil {
+		t.Fatal("one candidate was claimed by two rewrapped requests")
+	}
+	r.release(candidate)
+	if got := r.claim(&Conn{authKeyID: [8]byte{7}, sessionID: 5}, body); got != nil {
+		t.Fatal("fingerprint crossed the auth-key boundary")
+	}
+	if got := r.claim(c, []byte{4, 3, 2, 1}); got != nil {
+		t.Fatal("mismatched TL bytes claimed a candidate")
+	}
+	if got := r.claim(c, body); got != candidate {
+		t.Fatal("released candidate was lost from the fingerprint index")
+	}
+	r.release(candidate)
+	if r.total != 1 {
+		t.Fatalf("released claim retired candidate: total=%d", r.total)
+	}
+	r.acknowledge(c, 6)
+	if r.total != 0 || len(r.byKey) != 0 || len(r.bySession) != 0 || len(r.byRequest) != 0 {
+		t.Fatalf("ACK did not retire every candidate index: total=%d key=%d session=%d request=%d",
+			r.total, len(r.byKey), len(r.bySession), len(r.byRequest))
+	}
+}
+
+func TestInitRewrapAfterWritingReplaysWithoutBusinessExecution(t *testing.T) {
+	inner, wrapped := encodeRewrapTestRequest(t)
+	s := New(Options{RPCGlobalWorkers: 1, RPCGlobalMaxTasks: 16, RPCGlobalMaxBytes: 1 << 20})
+	transport := &collectingSessionTransport{}
+	key := newTestAuthKey(t)
+	c := s.newConn(transport, key, 88, 99)
+	defer c.ForceClose()
+
+	const oldReqID, newReqID = int64(3001), int64(4001)
+	oldPlan := &inboundPlan{items: []inboundItem{{
+		kind: inboundItemRPC, msgID: oldReqID, typeID: tg.HelpGetConfigRequestTypeID, body: inner,
+	}}}
+	defer oldPlan.close()
+	if err := s.prepareInboundRPCBatch(context.Background(), c, oldPlan); err != nil {
+		t.Fatalf("prepare old request: %v", err)
+	}
+	oldOwner := oldPlan.rpcOwners[0]
+	if got := (&encodedOutboundMessage{delivery: oldOwner.Delivery()}).beginWriting(); got != oldReqID {
+		t.Fatalf("old writing target = %d, want %d", got, oldReqID)
+	}
+
+	newPlan := &inboundPlan{items: []inboundItem{{
+		kind: inboundItemRPC, msgID: newReqID, typeID: tg.InvokeWithLayerRequestTypeID, body: wrapped,
+	}}}
+	defer newPlan.close()
+	if err := s.prepareInboundRPCBatch(context.Background(), c, newPlan); err != nil {
+		t.Fatalf("prepare rewrapped request: %v", err)
+	}
+	if len(newPlan.rpcTasks) != 0 || len(newPlan.rewrapAliases) != 1 {
+		t.Fatalf("late rewrap dispatched business: tasks=%d aliases=%d", len(newPlan.rpcTasks), len(newPlan.rewrapAliases))
+	}
+	if err := newPlan.commitRewrapAliases(s); err != nil {
+		t.Fatalf("activate late alias: %v", err)
+	}
+
+	encoded, err := s.encodeRPCResultContext(context.Background(), c, oldReqID, &mt.RPCError{
+		ErrorCode: 400, ErrorMessage: "TEST",
+	})
+	if err != nil {
+		t.Fatalf("encode old result: %v", err)
+	}
+	encoded.delivery = oldOwner.Delivery()
+	if !oldOwner.HandOff() {
+		t.Fatal("old owner handoff failed")
+	}
+	s.rpcResults.Put(c.authKeyID, c.sessionID, oldReqID, encoded)
+
+	deadline := time.Now().Add(2 * time.Second)
+	var replayed *encodedOutboundMessage
+	for time.Now().Before(deadline) {
+		if got, ok := s.rpcResults.Get(c.authKeyID, c.sessionID, newReqID); ok {
+			replayed = got
+			break
+		}
+		time.Sleep(time.Millisecond)
+	}
+	if replayed == nil {
+		t.Fatal("late alias did not publish a result under the new request ID")
+	}
+	if got := int64(binary.LittleEndian.Uint64(replayed.body[4:12])); got != newReqID {
+		t.Fatalf("replayed req_msg_id = %d, want %d", got, newReqID)
+	}
+	if len(transport.snapshot()) != 1 {
+		t.Fatalf("late alias physical result count = %d, want 1", len(transport.snapshot()))
+	}
+}
+
+func TestOutboundAckReturnsRPCRequestIDs(t *testing.T) {
+	state := outboundState{
+		pending: map[int64]*outboundFrame{
+			10: {msgID: 10, reqMsgID: 101},
+			20: {msgID: 20},
+		},
+		byRequest:   map[int64]int64{101: 10},
+		maxMessages: 8,
+	}
+	got := state.ack([]int64{10, 20, 30})
+	if len(got) != 1 || got[0] != 101 {
+		t.Fatalf("acked request IDs = %v, want [101]", got)
+	}
+}
+
+func TestInitRewrapAliasesExecutionAndRetargetsQueuedResult(t *testing.T) {
+	inner, wrapped := encodeRewrapTestRequest(t)
+	s := New(Options{RPCGlobalWorkers: 1, RPCGlobalMaxTasks: 16, RPCGlobalMaxBytes: 1 << 20})
+	c := &Conn{
+		metrics: NopMetrics{}, authKeyID: [8]byte{9}, authKeyHex: "09",
+		sessionID: 77, key: crypto.AuthKey{ID: [8]byte{9}},
+	}
+	c.startInboundRPCScheduler(s.rpcScheduler, 1, 8, time.Second)
+	defer c.closeInboundRPCScheduler()
+
+	const oldReqID, newReqID = int64(1001), int64(2001)
+	oldPlan := &inboundPlan{items: []inboundItem{{
+		kind: inboundItemRPC, msgID: oldReqID, typeID: tg.HelpGetConfigRequestTypeID, body: inner,
+	}}}
+	defer oldPlan.close()
+	if err := s.prepareInboundRPCBatch(context.Background(), c, oldPlan); err != nil {
+		t.Fatalf("prepare old request: %v", err)
+	}
+	if len(oldPlan.rpcTasks) != 1 || len(oldPlan.rpcOwners) != 1 {
+		t.Fatalf("old admission tasks=%d owners=%d", len(oldPlan.rpcTasks), len(oldPlan.rpcOwners))
+	}
+	oldOwner := oldPlan.rpcOwners[0]
+
+	newPlan := &inboundPlan{items: []inboundItem{{
+		kind: inboundItemRPC, msgID: newReqID, typeID: tg.InvokeWithLayerRequestTypeID, body: wrapped,
+	}}}
+	defer newPlan.close()
+	if err := s.prepareInboundRPCBatch(context.Background(), c, newPlan); err != nil {
+		t.Fatalf("prepare rewrapped request: %v", err)
+	}
+	if len(newPlan.rpcTasks) != 0 || len(newPlan.rewrapAliases) != 1 || newPlan.items[0].kind != inboundItemRewrappedRPC {
+		t.Fatalf("rewrap admission tasks=%d aliases=%d kind=%d", len(newPlan.rpcTasks), len(newPlan.rewrapAliases), newPlan.items[0].kind)
+	}
+	if err := newPlan.commitRewrapAliases(s); err != nil {
+		t.Fatalf("activate alias: %v", err)
+	}
+
+	encoded, err := s.encodeRPCResultContext(context.Background(), c, oldReqID, &mt.RPCError{
+		ErrorCode: 400, ErrorMessage: "TEST",
+	})
+	if err != nil {
+		t.Fatalf("encode old result: %v", err)
+	}
+	encoded.delivery = oldOwner.Delivery()
+	encoded.markQueued()
+	if got := encoded.beginWriting(); got != newReqID {
+		t.Fatalf("physical result target = %d, want new req %d", got, newReqID)
+	}
+	if !oldOwner.HandOff() {
+		t.Fatal("old owner handoff failed")
+	}
+	encoded.markDelivered()
+	s.rpcResults.Put(c.authKeyID, c.sessionID, oldReqID, encoded)
+
+	aliased, ok := s.rpcResults.Get(c.authKeyID, c.sessionID, newReqID)
+	if !ok {
+		t.Fatal("new req_msg_id result was not completed")
+	}
+	if got := int64(binary.LittleEndian.Uint64(aliased.body[4:12])); got != newReqID {
+		t.Fatalf("cached aliased req_msg_id = %d, want %d", got, newReqID)
+	}
+	if s.rpcRewrap.total != 0 {
+		t.Fatalf("rewrap registry retained %d consumed candidates", s.rpcRewrap.total)
+	}
+}

internal/mtprotoedge/same_port_mux.go

@@ -34,6 +34,7 @@ type samePortMux struct {
 	base         net.Listener
 	addr         net.Addr
 	sniffTimeout time.Duration
+	observe      func(connectionIntakeEvent)
 
 	tcp  *samePortMuxListener
 	http *samePortMuxListener
@@ -49,7 +50,7 @@ type samePortMux struct {
 	sniffing map[net.Conn]struct{}
 }
 
-func newSamePortMux(base net.Listener, sniffTimeout time.Duration) *samePortMux {
+func newSamePortMux(base net.Listener, sniffTimeout time.Duration, observers ...func(connectionIntakeEvent)) *samePortMux {
 	if sniffTimeout <= 0 {
 		sniffTimeout = 5 * time.Second
 	}
@@ -60,6 +61,9 @@ func newSamePortMux(base net.Listener, sniffTimeout time.Duration) *samePortMux
 		closed:       make(chan struct{}),
 		sniffing:     make(map[net.Conn]struct{}),
 	}
+	if len(observers) > 0 {
+		m.observe = observers[0]
+	}
 	m.tcp = newSamePortMuxListener(m.addr, m.closed)
 	m.http = newSamePortMuxListener(m.addr, m.closed)
 	return m
@@ -144,10 +148,13 @@ func (m *samePortMux) Close() error {
 // dispatch 窥探单条连接的前 4 字节并把它交给 tcp 或 http 子 listener。窥探带 sniffTimeout
 // 读上界，慢/半开连接最多占用本 goroutine sniffTimeout 后即被回收。
 func (m *samePortMux) dispatch(ctx context.Context, conn net.Conn) {
+	started := time.Now()
+	remote, local := connRemote(conn), connLocal(conn)
 	// SetReadDeadline bounds an otherwise healthy slow-loris connection, but Close only owns
 	// the base listener, not sockets Accept has already returned. Register temporary ownership so
 	// mux shutdown can close this read immediately. finishSniff removes the socket before hand-off.
 	if !m.beginSniff(conn) {
+		m.observeEvent(connectionIntakeEvent{stage: "mux_sniff", outcome: "closed", remote: remote, local: local, duration: time.Since(started)})
 		_ = conn.Close()
 		return
 	}
@@ -160,10 +167,16 @@ func (m *samePortMux) dispatch(ctx context.Context, conn net.Conn) {
 
 	var header [4]byte
 	if err := conn.SetReadDeadline(time.Now().Add(m.sniffTimeout)); err != nil {
+		m.observeEvent(connectionIntakeEvent{stage: "mux_sniff", outcome: "error", remote: remote, local: local, duration: time.Since(started), err: err})
 		_ = conn.Close()
 		return
 	}
 	if _, err := io.ReadFull(conn, header[:]); err != nil {
+		outcome := "error"
+		if isClientDisconnect(err) {
+			outcome = "client_disconnect"
+		}
+		m.observeEvent(connectionIntakeEvent{stage: "mux_sniff", outcome: outcome, remote: remote, local: local, duration: time.Since(started), err: err})
 		_ = conn.Close()
 		return
 	}
@@ -171,11 +184,13 @@ func (m *samePortMux) dispatch(ctx context.Context, conn net.Conn) {
 	// registry entry under sniffMu is the hand-off barrier: Close either captured and closed this
 	// socket, or it can no longer find it. A concurrently closed mux refuses delivery.
 	if !m.finishSniff(conn) {
+		m.observeEvent(connectionIntakeEvent{stage: "mux_sniff", outcome: "closed", remote: remote, local: local, duration: time.Since(started)})
 		_ = conn.Close()
 		return
 	}
 	finishedSniff = true
 	if err := conn.SetReadDeadline(time.Time{}); err != nil {
+		m.observeEvent(connectionIntakeEvent{stage: "mux_sniff", outcome: "error", remote: remote, local: local, duration: time.Since(started), err: err})
 		_ = conn.Close()
 		return
 	}
@@ -186,14 +201,24 @@ func (m *samePortMux) dispatch(ctx context.Context, conn net.Conn) {
 	}
 
 	target := m.tcp
+	transport := "tcp"
 	if isHTTPHeaderPrefix(header) {
 		target = m.http
+		transport = "websocket"
 	}
+	m.observeEvent(connectionIntakeEvent{stage: "mux_sniff", outcome: "ready", transport: transport, remote: remote, local: local, duration: time.Since(started), bytes: len(header)})
 	if !target.deliver(ctx, wrapped) {
+		m.observeEvent(connectionIntakeEvent{stage: "mux_delivery", outcome: "closed", transport: transport, remote: remote, local: local, duration: time.Since(started)})
 		_ = conn.Close()
 	}
 }
 
+func (m *samePortMux) observeEvent(event connectionIntakeEvent) {
+	if m.observe != nil {
+		m.observe(event)
+	}
+}
+
 func (m *samePortMux) beginSniff(conn net.Conn) bool {
 	m.sniffMu.Lock()
 	defer m.sniffMu.Unlock()

internal/mtprotoedge/server.go

@@ -43,6 +43,27 @@ type RPCHandler interface {
 	NegotiatedLayer(authKeyID [8]byte, sessionID int64) (int, bool)
 }
 
+// RPCHandlerWithMethod returns the canonical innermost RPC method after the
+// router has peeled invokeWithLayer/initConnection/invokeAfter wrappers. Egress
+// scheduling must use this identity: the outer wrapper is not a useful signal
+// for prioritizing updates convergence over catalog/media responses.
+type RPCHandlerWithMethod interface {
+	DispatchWithMethod(ctx context.Context, authKeyID [8]byte, sessionID int64, b *bin.Buffer) (bin.Encoder, string, error)
+}
+
+// RPCInitConnectionObserver records wrapper metadata when the edge aliases an
+// initConnection reissue to an already-running request and therefore correctly
+// skips a second business Dispatch.
+type RPCInitConnectionObserver interface {
+	ObserveInitConnection(
+		ctx context.Context,
+		authKeyID [8]byte,
+		sessionID int64,
+		layer, apiID int,
+		deviceModel, systemVersion, appVersion, systemLangCode, langPack, langCode string,
+	) error
+}
+
 // Options 配置 Server。
 type Options struct {
 	// Logger 日志器。默认 zap.NewNop()。
@@ -126,6 +147,10 @@ type Options struct {
 	RPC RPCHandler
 	// Metrics 接收连接层指标。默认 NopMetrics。
 	Metrics Metrics
+	// OnServing is called after the connection intake loops have been installed.
+	// It is a platform-neutral observation hook; all slow initialization must
+	// finish before ListenAndServe is entered.
+	OnServing func(net.Addr)
 	// Clock 用于消息 ID 与时间戳。默认 clock.System。
 	Clock clock.Clock
 	// Rand 随机源。默认 crypto.DefaultRand()。
@@ -239,6 +264,7 @@ type Server struct {
 	conns     *SessionManager
 	rpc       RPCHandler
 	metrics   Metrics
+	onServing func(net.Addr)
 	cipher    crypto.Cipher
 	clock     clock.Clock
 	rand      io.Reader
@@ -246,6 +272,7 @@ type Server struct {
 	admission *admissionController
 
 	rpcResults *rpcResultCache
+	rpcRewrap  *rpcRewrapRegistry
 
 	// onFrame 是测试钩子：收到一帧时回调其字节数；生产为 nil。
 	onFrame func(n int)
@@ -284,15 +311,30 @@ func New(opts Options) *Server {
 		conns:                    conns,
 		rpc:                      opts.RPC,
 		metrics:                  opts.Metrics,
+		onServing:                opts.OnServing,
 		cipher:                   crypto.NewServerCipher(opts.Rand),
 		clock:                    opts.Clock,
 		rand:                     opts.Rand,
 		types:                    tmap.New(tg.TypesMap(), mt.TypesMap(), proto.TypesMap()),
 		rpcResults:               newRPCResultCacheWithFlightLimit(opts.Clock.Now, opts.RPCGlobalMaxTasks),
+		rpcRewrap:                newRPCRewrapRegistry(opts.RPCGlobalMaxTasks),
 		admission:                newAdmissionController(opts.MaxConnections, opts.MaxConnectionsPerIP, opts.MaxConcurrentHandshakes),
 	}
 }
 
+// ListenAndServe binds the public MTProto socket and immediately enters Serve.
+// Keeping listener ownership at the connection edge prevents callers from
+// exposing a TCP port and then performing slow seed/cache initialization while
+// clients are already completing handshakes into an unread accept backlog.
+func (s *Server) ListenAndServe(ctx context.Context, addr string) error {
+	var lc net.ListenConfig
+	ln, err := lc.Listen(ctx, "tcp", addr)
+	if err != nil {
+		return fmt.Errorf("listen %q: %w", addr, err)
+	}
+	return s.Serve(ctx, ln)
+}
+
 // newConn 基于一次解密结果创建一个可发送的连接对象。
 func (s *Server) newConn(tc transport.Conn, key crypto.AuthKey, sessionID, salt int64) *Conn {
 	if lease, ok := tc.(*physicalTransportLease); ok {
@@ -338,6 +380,7 @@ func (s *Server) buildConn(tc transport.Conn, lease *physicalTransportLease, key
 		outboundTrackedBudget:        s.outboundTrackedBudget,
 		outboundControlTrackedBudget: s.outboundControlBudget,
 		outboundScratchPool:          s.outboundScratchPool,
+		rpcResultAcked:               s.rpcRewrap.acknowledge,
 	}
 	c.startOutbound()
 	c.startInboundRPCScheduler(s.rpcScheduler, s.rpcInflight, s.rpcQueueSize, s.rpcTimeout)
@@ -354,7 +397,7 @@ func (s *Server) Serve(ctx context.Context, ln net.Listener) error {
 	defer s.rpcScheduler.stop(rpcCloseWaitTimeout)
 	// 只在最外层 listener 包一次，确保 same-port mux 的 sniff/HTTP upgrade 也计入
 	// raw admission，而不是等连接已经分流后才计数。
-	ln = s.admission.wrapListener(ln)
+	ln = s.observeRawAccepts(s.admission.wrapListener(ln))
 	if s.websocket {
 		return s.serveMixed(ctx, ln)
 	}
@@ -367,8 +410,12 @@ func (s *Server) serveTCP(ctx context.Context, ln net.Listener) error {
 
 	s.log.Info("Serving", zap.String("addr", ln.Addr().String()), zap.Int("dc", s.dc), zap.Bool("obfuscated_tcp", s.obfuscated))
 	defer s.log.Info("Stopped")
-
-	return s.acceptLoop(ctx, ln, s.obfuscated)
+	errCh := make(chan error, 1)
+	go func() {
+		errCh <- s.acceptLoop(ctx, ln, s.obfuscated)
+	}()
+	s.signalServing(ln.Addr())
+	return <-errCh
 }
 
 func (s *Server) serveMixed(ctx context.Context, ln net.Listener) error {
@@ -382,7 +429,7 @@ func (s *Server) serveMixed(ctx context.Context, ln net.Listener) error {
 	// minDuration(5s,...) 把嗅探压到 5s，比非 mux 路径激进 12 倍，会把这些暖连接在 5s 误杀，
 	// 触发客户端 6s 重连风暴并误判「后端不健康」回退到外部 DNS。per-conn goroutine 模型已消解
 	// slow-loris 接入饥饿，故嗅探用满 handshakeTimeout 是安全的。
-	mux := newSamePortMux(ln, s.handshakeTimeout)
+	mux := newSamePortMux(ln, s.handshakeTimeout, s.observeConnectionIntake)
 	wsRawLn, wsHandler := transport.WebsocketListener(ln.Addr())
 	wsLn := newTransportPacketMessageListener(wsRawLn)
 
@@ -430,7 +477,7 @@ func (s *Server) serveMixed(ctx context.Context, ln net.Listener) error {
 	// WebSocket：gotd 升级处理器已剥离 obfuscated2 并补回 codec tag，这里只需探测 codec。
 	go func() {
 		defer wg.Done()
-		errCh <- s.acceptLoop(ctx, wsLn, false)
+		errCh <- s.acceptLoopTransport(ctx, wsLn, false, "websocket")
 	}()
 	go func() {
 		defer wg.Done()
@@ -444,6 +491,7 @@ func (s *Server) serveMixed(ctx context.Context, ln net.Listener) error {
 		}
 		errCh <- nil
 	}()
+	s.signalServing(ln.Addr())
 
 	// The four services form one lifecycle: even a clean/closed-listener return from any one
 	// component means the remaining three can no longer make forward progress as a complete
@@ -468,6 +516,10 @@ func (s *Server) serveMixed(ctx context.Context, ln net.Listener) error {
 // 整个监听循环。obfuscated 为 true 时先走 obfuscated2 去混淆（裸 MTProto TCP）；WebSocket
 // 连接传 false（gotd 升级处理器已完成去混淆）。
 func (s *Server) acceptLoop(ctx context.Context, ln net.Listener, obfuscated bool) error {
+	return s.acceptLoopTransport(ctx, ln, obfuscated, intakeTransport(obfuscated))
+}
+
+func (s *Server) acceptLoopTransport(ctx context.Context, ln net.Listener, obfuscated bool, transportName string) error {
 	ctx, cancel := context.WithCancel(ctx)
 	var wg sync.WaitGroup
 	defer func() {
@@ -505,7 +557,14 @@ func (s *Server) acceptLoop(ctx context.Context, ln net.Listener, obfuscated boo
 		wg.Add(1)
 		go func() {
 			defer wg.Done()
-			s.serveDetectedConn(ctx, raw, obfuscated)
+			s.observeConnectionIntake(connectionIntakeEvent{
+				stage:     "transport_dispatch",
+				outcome:   "accepted",
+				transport: transportName,
+				remote:    connRemote(raw),
+				local:     connLocal(raw),
+			})
+			s.serveDetectedConn(ctx, raw, obfuscated, transportName)
 		}()
 	}
 }
@@ -513,7 +572,9 @@ func (s *Server) acceptLoop(ctx context.Context, ln net.Listener, obfuscated boo
 // serveDetectedConn 把一条裸连接提升为 transport.Conn（去混淆 + codec 探测）后运行 MTProto
 // 连接循环。提升过程的读取放在本 goroutine、且受握手读超时约束，而非塞在 accept 循环里，
 // 这样慢连接不会阻塞其他连接接入，去混淆/codec 握手本身也有时间上界。
-func (s *Server) serveDetectedConn(ctx context.Context, raw net.Conn, obfuscated bool) {
+func (s *Server) serveDetectedConn(ctx context.Context, raw net.Conn, obfuscated bool, transportName string) {
+	started := time.Now()
+	remote, local := connRemote(raw), connLocal(raw)
 	// 握手读超时只覆盖去混淆 + codec 探测这一小段；用真实墙钟时间（SetReadDeadline 语义），
 	// 不走可能被测试注入的逻辑 clock。
 	if err := raw.SetReadDeadline(time.Now().Add(s.handshakeTimeout)); err != nil {
@@ -536,21 +597,37 @@ func (s *Server) serveDetectedConn(ctx context.Context, raw net.Conn, obfuscated
 	conn, err := s.promoteConn(raw, obfuscated)
 	close(promoted)
 	if err != nil {
-		// 去混淆/codec 探测失败（读超时、客户端中途断开、坏 init 等）只影响这一条连接，
-		// 记 debug 即可。
-		if !isClientDisconnect(err) {
-			s.log.Debug("Transport handshake failed", zap.Error(err))
+		outcome := "error"
+		if isClientDisconnect(err) {
+			outcome = "client_disconnect"
 		}
+		s.observeConnectionIntake(connectionIntakeEvent{
+			stage:     "transport_promote",
+			outcome:   outcome,
+			transport: transportName,
+			remote:    remote,
+			local:     local,
+			duration:  time.Since(started),
+			err:       err,
+		})
 		_ = raw.Close()
 		return
 	}
+	s.observeConnectionIntake(connectionIntakeEvent{
+		stage:     "transport_promote",
+		outcome:   "ready",
+		transport: transportName,
+		remote:    remote,
+		local:     local,
+		duration:  time.Since(started),
+	})
 	// 探测完成，撤掉握手读超时；后续每帧读写由 serveConn / 传输层各自管理超时。
 	if err := raw.SetReadDeadline(time.Time{}); err != nil {
 		_ = conn.Close()
 		return
 	}
-	if err := s.serveConn(ctx, conn); err != nil && !isClientDisconnect(err) {
-		s.log.Info("Connection closed with error", zap.Error(err))
+	if err := s.serveConn(ctx, conn, remote, local); err != nil && !isClientDisconnect(err) {
+		s.log.Info("Connection closed with error", zap.String("remote_addr", remote), zap.String("local_addr", local), zap.Error(err))
 	}
 }
 
@@ -572,12 +649,14 @@ func (s *Server) promoteConn(raw net.Conn, obfuscated bool) (transport.Conn, err
 //   - auth_key_id 未注册：回 AuthKeyNotFound，促使客户端重新握手。
 //
 // 连接建立 session 后注册到 SessionManager，结束时注销。
-func (s *Server) serveConn(ctx context.Context, raw transport.Conn) (err error) {
+func (s *Server) serveConn(ctx context.Context, raw transport.Conn, remote, local string) (err error) {
 	transportOwner, conn := newPhysicalTransportOwner(raw)
 	s.metrics.ConnOpened()
-	s.log.Debug("Connection accepted")
+	s.log.Debug("MTProto connection loop started", zap.String("remote_addr", remote), zap.String("local_addr", local))
 
 	var current *Conn
+	firstFrameStarted := time.Now()
+	firstFrameSeen := false
 	defer func() {
 		// A successful Recv transfers the frame reservation to serveConn. Release it only after
 		// this stack has stopped using b/plain; transport.Close may have raced us earlier and must
@@ -595,7 +674,7 @@ func (s *Server) serveConn(ctx context.Context, raw transport.Conn) (err error)
 			current.Close()
 		}
 		s.metrics.ConnClosed()
-		s.log.Debug("Connection closed", zap.Error(err))
+		s.log.Debug("Connection closed", zap.String("remote_addr", remote), zap.String("local_addr", local), zap.Error(err))
 	}()
 
 	// ctx 取消或处理结束时关闭连接，解除 Recv 阻塞。
@@ -624,8 +703,25 @@ func (s *Server) serveConn(ctx context.Context, raw transport.Conn) (err error)
 				timeout = s.handshakeTimeout
 			}
 			if err := s.recv(ctx, conn, &b, timeout); err != nil {
+				if !firstFrameSeen {
+					outcome := "error"
+					if isClientDisconnect(err) {
+						outcome = "client_disconnect"
+					}
+					s.observeConnectionIntake(connectionIntakeEvent{
+						stage: "first_frame", outcome: outcome, remote: remote, local: local,
+						duration: time.Since(firstFrameStarted), err: err,
+					})
+				}
 				return err
 			}
+			if !firstFrameSeen {
+				firstFrameSeen = true
+				s.observeConnectionIntake(connectionIntakeEvent{
+					stage: "first_frame", outcome: "ready", remote: remote, local: local,
+					duration: time.Since(firstFrameStarted), bytes: b.Len(),
+				})
+			}
 			if s.onFrame != nil {
 				s.onFrame(b.Len())
 			}
@@ -742,6 +838,7 @@ func (s *Server) recv(ctx context.Context, conn transport.Conn, b *bin.Buffer, t
 func isClientDisconnect(err error) bool {
 	switch {
 	case errors.Is(err, io.EOF),
+		errors.Is(err, io.ErrUnexpectedEOF),
 		errors.Is(err, net.ErrClosed),
 		errors.Is(err, context.Canceled),
 		errors.Is(err, context.DeadlineExceeded):

internal/mtprotoedge/session_barrier_integration_test.go

@@ -492,29 +492,28 @@ func TestCrossConnectionInflightRPCHasOneBusinessOwnerAndReplaysResult(t *testin
 	if got := handler.calls.Load(); got != 1 {
 		t.Fatalf("overlapping reconnect executed %d business handlers, want 1", got)
 	}
-	select {
-	case got := <-secondDone:
-		t.Fatalf("duplicate reconnect returned before owner completion: %v", got.err)
-	default:
-	}
-
-	close(handler.release)
 	var second handleResult
 	select {
 	case second = <-secondDone:
-	case <-time.After(3 * time.Second):
-		t.Fatal("duplicate reconnect did not receive owner result")
+	case <-time.After(time.Second):
+		t.Fatal("event-driven duplicate admission blocked the replacement read loop")
 	}
 	if second.err != nil {
 		t.Fatalf("second handleEncrypted: %v", second.err)
 	}
 	if second.conn == nil || !second.conn.isActive() {
-		t.Fatalf("second connection was not active after replay: %p", second.conn)
+		t.Fatalf("second connection was not active after non-blocking admission: %p", second.conn)
 	}
+
+	close(handler.release)
 	if got := handler.calls.Load(); got != 1 {
 		t.Fatalf("cross-connection duplicate business calls = %d, want 1", got)
 	}
 
+	deadline = time.Now().Add(3 * time.Second)
+	for len(secondTransport.snapshot()) < 3 && time.Now().Before(deadline) {
+		time.Sleep(time.Millisecond)
+	}
 	resultCount := 0
 	for _, wire := range secondTransport.snapshot() {
 		data, decryptErr := crypto.NewClientCipher(rand.Reader).DecryptFromBuffer(key, &bin.Buffer{Buf: wire})
@@ -582,9 +581,34 @@ func TestCrossConnectionInflightAbortRetriesOnlyAfterOldOwnerStops(t *testing.T)
 	secondState := newConnState()
 	var secondPlain bin.Buffer
 	secondConn, err := s.handleEncrypted(context.Background(), secondTransport, secondState, nil, &stored, secondFrame, &secondPlain)
-	if err != nil {
+	if err != nil && !errors.Is(err, ErrConnClosed) {
 		t.Fatalf("second handleEncrypted: %v", err)
 	}
+	if secondConn == nil {
+		t.Fatal("second handleEncrypted returned no logical connection")
+	}
+	deadline := time.Now().Add(2 * time.Second)
+	for (handler.active.Load() != 0 || !secondConn.isRetired()) && time.Now().Before(deadline) {
+		time.Sleep(time.Millisecond)
+	}
+	if got := handler.calls.Load(); got != 1 {
+		t.Fatalf("event subscription re-executed aborted owner: calls=%d", got)
+	}
+	if handler.active.Load() != 0 || secondConn == nil || !secondConn.isRetired() {
+		t.Fatalf("abort convergence = active:%d second:%p state:%v", handler.active.Load(), secondConn, secondConn.lifecycleState())
+	}
+
+	// The aborted owner has now definitively stopped and the subscribed
+	// replacement generation is fenced. A fresh physical retry may acquire the
+	// same msg_id and execute, still with max concurrency one.
+	thirdFrame, _ := encryptedRPCFrameForBarrierTest(t, key, salt, sessionID, msgID)
+	thirdTransport := &collectingSessionTransport{}
+	thirdState := newConnState()
+	var thirdPlain bin.Buffer
+	thirdConn, err := s.handleEncrypted(context.Background(), thirdTransport, thirdState, nil, &stored, thirdFrame, &thirdPlain)
+	if err != nil {
+		t.Fatalf("third handleEncrypted: %v", err)
+	}
 	waitForAtomicCalls(t, &handler.calls, 2)
 	waitInboundRPCBatchBudget(t, s.rpcScheduler, 0, 0)
 	if got := handler.max.Load(); got != 1 {
@@ -595,7 +619,11 @@ func TestCrossConnectionInflightAbortRetriesOnlyAfterOldOwnerStops(t *testing.T)
 	}
 
 	resultCount := 0
-	for _, wire := range secondTransport.snapshot() {
+	deadline = time.Now().Add(2 * time.Second)
+	for len(thirdTransport.snapshot()) < 3 && time.Now().Before(deadline) {
+		time.Sleep(time.Millisecond)
+	}
+	for _, wire := range thirdTransport.snapshot() {
 		data, decryptErr := crypto.NewClientCipher(rand.Reader).DecryptFromBuffer(key, &bin.Buffer{Buf: wire})
 		if decryptErr != nil {
 			t.Fatalf("decrypt sequential-retry reply: %v", decryptErr)
@@ -612,10 +640,10 @@ func TestCrossConnectionInflightAbortRetriesOnlyAfterOldOwnerStops(t *testing.T)
 	if resultCount != 1 {
 		t.Fatalf("sequential retry result count = %d, want 1", resultCount)
 	}
-	if !firstConn.isRetired() || secondConn == nil || !secondConn.isActive() {
-		t.Fatalf("replacement lifecycle = old:%v new:%p active:%v", firstConn.lifecycleState(), secondConn, secondConn != nil && secondConn.isActive())
+	if !firstConn.isRetired() || !secondConn.isRetired() || thirdConn == nil || !thirdConn.isActive() {
+		t.Fatalf("replacement lifecycle = first:%v second:%v third:%p active:%v", firstConn.lifecycleState(), secondConn.lifecycleState(), thirdConn, thirdConn != nil && thirdConn.isActive())
 	}
-	secondConn.ForceClose()
+	thirdConn.ForceClose()
 }
 
 func waitForAtomicCalls(t *testing.T, calls interface{ Load() int32 }, want int32) {

internal/mtprotoedge/transport_compat.go

@@ -26,6 +26,9 @@ const quickAckResponseFlag = uint32(1 << 31)
 const (
 	maxCompatPacketOverhead         = 7 // 4-byte header + up to 3 bytes padded-intermediate padding.
 	maxRetainedDirectMessageScratch = 64 << 10
+	progressiveWriteMinBytes        = 64 << 10
+	progressiveWriteChunkBytes      = 32 << 10
+	progressiveWriteIdleTimeout     = 10 * time.Second
 )
 
 type transportListener interface {
@@ -237,12 +240,83 @@ func (c *compatTransportConn) sendDeadline(deadline time.Time, b *bin.Buffer, sc
 		}
 		return nil
 	}
-	if err := c.codec.Write(c.conn, b); err != nil {
+	writer := io.Writer(c.conn)
+	// A transport packet is still physically serialized as one uninterrupted
+	// byte sequence. Only large raw-TCP payloads use bounded chunks so progress
+	// refreshes the idle deadline and a stalled link reports how far it got.
+	if b.Len() >= progressiveWriteMinBytes {
+		writer = &progressiveDeadlineWriter{
+			conn: c.conn, hardDeadline: deadline,
+			idleTimeout: progressiveWriteIdleTimeout, chunkBytes: progressiveWriteChunkBytes,
+		}
+	}
+	if err := c.codec.Write(writer, b); err != nil {
 		return errors.Wrap(err, "write")
 	}
 	return nil
 }
 
+type progressiveWriteError struct {
+	Written int
+	Chunks  int
+	Err     error
+}
+
+func (e *progressiveWriteError) Error() string {
+	return fmt.Sprintf("progressive transport write after %d bytes/%d chunks: %v", e.Written, e.Chunks, e.Err)
+}
+
+func (e *progressiveWriteError) Unwrap() error { return e.Err }
+
+type progressiveDeadlineWriter struct {
+	conn         net.Conn
+	hardDeadline time.Time
+	idleTimeout  time.Duration
+	chunkBytes   int
+	written      int
+	chunks       int
+}
+
+func (w *progressiveDeadlineWriter) Write(p []byte) (int, error) {
+	if w == nil || w.conn == nil {
+		return 0, io.ErrClosedPipe
+	}
+	startWritten := w.written
+	chunkBytes := w.chunkBytes
+	if chunkBytes <= 0 {
+		chunkBytes = progressiveWriteChunkBytes
+	}
+	for len(p) > 0 {
+		deadline := w.hardDeadline
+		if w.idleTimeout > 0 {
+			idle := time.Now().Add(w.idleTimeout)
+			if deadline.IsZero() || idle.Before(deadline) {
+				deadline = idle
+			}
+		}
+		if err := w.conn.SetWriteDeadline(deadline); err != nil {
+			return w.written - startWritten, &progressiveWriteError{Written: w.written, Chunks: w.chunks, Err: err}
+		}
+		chunk := p
+		if len(chunk) > chunkBytes {
+			chunk = chunk[:chunkBytes]
+		}
+		n, err := w.conn.Write(chunk)
+		w.written += n
+		if n > 0 {
+			w.chunks++
+			p = p[n:]
+		}
+		if err != nil {
+			return w.written - startWritten, &progressiveWriteError{Written: w.written, Chunks: w.chunks, Err: err}
+		}
+		if n == 0 {
+			return w.written - startWritten, &progressiveWriteError{Written: w.written, Chunks: w.chunks, Err: io.ErrShortWrite}
+		}
+	}
+	return w.written - startWritten, nil
+}
+
 func (c *compatTransportConn) writeTransportPacketMessage(b *bin.Buffer, scratch *[]byte) error {
 	required := b.Len() + maxCompatPacketOverhead
 	if cap(*scratch) < required {

internal/mtprotoedge/transport_compat_test.go

@@ -15,6 +15,7 @@ type messageWriteTestConn struct {
 	bytes.Buffer
 	writes    int
 	maxWrite  int
+	deadlines []time.Time
 }
 
 func (c *messageWriteTestConn) Read([]byte) (int, error) { return 0, io.EOF }
@@ -30,7 +31,10 @@ func (*messageWriteTestConn) LocalAddr() net.Addr              { return messageW
 func (*messageWriteTestConn) RemoteAddr() net.Addr            { return messageWriteTestAddr("remote") }
 func (*messageWriteTestConn) SetDeadline(time.Time) error     { return nil }
 func (*messageWriteTestConn) SetReadDeadline(time.Time) error { return nil }
-func (*messageWriteTestConn) SetWriteDeadline(time.Time) error { return nil }
+func (c *messageWriteTestConn) SetWriteDeadline(d time.Time) error {
+	c.deadlines = append(c.deadlines, d)
+	return nil
+}
 
 type messageWriteTestAddr string
 
@@ -42,6 +46,33 @@ type countWriteBuffer struct {
 	writes int
 }
 
+func TestProgressiveDeadlineWriterChunksLargeRawPacket(t *testing.T) {
+	raw := &messageWriteTestConn{maxWrite: 8 << 10}
+	hard := time.Now().Add(time.Minute)
+	w := &progressiveDeadlineWriter{
+		conn: raw, hardDeadline: hard, idleTimeout: time.Second, chunkBytes: 32 << 10,
+	}
+	payload := bytes.Repeat([]byte{0x5a}, 192<<10)
+	n, err := w.Write(payload)
+	if err != nil {
+		t.Fatalf("progressive write: %v", err)
+	}
+	if n != len(payload) || !bytes.Equal(raw.Bytes(), payload) {
+		t.Fatalf("progressive write bytes = %d/%d", n, len(raw.Bytes()))
+	}
+	if raw.writes < len(payload)/(8<<10) {
+		t.Fatalf("physical chunks = %d, want progress across partial writes", raw.writes)
+	}
+	if len(raw.deadlines) != raw.writes {
+		t.Fatalf("deadline refreshes = %d, writes = %d", len(raw.deadlines), raw.writes)
+	}
+	for _, deadline := range raw.deadlines {
+		if deadline.After(hard) {
+			t.Fatalf("idle deadline %v exceeded hard deadline %v", deadline, hard)
+		}
+	}
+}
+
 func (w *countWriteBuffer) Write(p []byte) (int, error) {
 	w.writes++
 	return w.Buffer.Write(p)
@@ -158,6 +189,30 @@ func TestCompatTransportCodecsWriteSegmentedPacketWithoutFullCopy(t *testing.T)
 	})
 }
 
+func TestCompatRawTransportUsesProgressiveWriterForLargePacket(t *testing.T) {
+	var payload bin.Buffer
+	payload.Put(bytes.Repeat([]byte{0x6b}, 192<<10))
+	raw := &messageWriteTestConn{maxWrite: 8 << 10}
+	conn := &compatTransportConn{conn: raw, codec: &quickAckAbridgedCodec{}}
+	if err := conn.SendDeadline(time.Now().Add(time.Minute), &payload); err != nil {
+		t.Fatalf("send large raw packet: %v", err)
+	}
+	if raw.writes < 20 {
+		t.Fatalf("large raw packet writes = %d, want observable progressive chunks", raw.writes)
+	}
+	if len(raw.deadlines) != raw.writes+1 { // initial hard deadline + one per progress write.
+		t.Fatalf("large packet deadline updates = %d, writes = %d", len(raw.deadlines), raw.writes)
+	}
+	var decoded bin.Buffer
+	requested, err := readQuickAckAbridged(bytes.NewReader(raw.Bytes()), &decoded)
+	if err != nil {
+		t.Fatalf("read large packet: %v", err)
+	}
+	if requested || !bytes.Equal(decoded.Raw(), payload.Raw()) {
+		t.Fatal("progressive raw write changed transport packet")
+	}
+}
+
 func TestCompatTransportWebSocketWritesOneMessagePerPacket(t *testing.T) {
 	var payload bin.Buffer
 	payload.PutInt32(0x01020304)

internal/postresponse/callbacks.go

@@ -39,15 +39,34 @@ func Register(ctx context.Context, cb func()) bool {
 }
 
 func Run(ctx context.Context) {
+	run := Take(ctx)
+	if run != nil {
+		run()
+	}
+}
+
+// Take transfers ownership of every currently registered callback to the caller.
+// The returned function is idempotent and may safely outlive the request context.
+// MTProto uses this to release a business worker after admitting rpc_result while
+// still delaying follow-up updates until the result reaches the reliable stream.
+func Take(ctx context.Context) func() {
 	cbs, ok := ctx.Value(callbacksKey{}).(*callbacks)
 	if !ok || cbs == nil {
-		return
+		return nil
 	}
 	cbs.mu.Lock()
 	list := append([]callback(nil), cbs.list...)
 	cbs.list = nil
 	cbs.mu.Unlock()
+	if len(list) == 0 {
+		return nil
+	}
+	var once sync.Once
+	return func() {
+		once.Do(func() {
 			for _, cb := range list {
 				cb()
 			}
+		})
+	}
 }

internal/postresponse/callbacks_test.go

@@ -0,0 +1,28 @@
+package postresponse
+
+import (
+	"context"
+	"sync/atomic"
+	"testing"
+)
+
+func TestTakeTransfersCallbacksAndRunsOnce(t *testing.T) {
+	ctx := WithCallbacks(context.Background())
+	var calls atomic.Int32
+	if !Register(ctx, func() { calls.Add(1) }) || !Register(ctx, func() { calls.Add(1) }) {
+		t.Fatal("register callbacks")
+	}
+	run := Take(ctx)
+	if run == nil {
+		t.Fatal("Take returned no callback")
+	}
+	Run(ctx)
+	if got := calls.Load(); got != 0 {
+		t.Fatalf("callbacks remained attached after Take: %d", got)
+	}
+	run()
+	run()
+	if got := calls.Load(); got != 2 {
+		t.Fatalf("transferred callbacks ran %d times, want 2 total", got)
+	}
+}

internal/rpc/router.go

@@ -218,23 +218,31 @@ func New(cfg Config, deps Deps, log *zap.Logger, clk clock.Clock) *Router {
 	return r
 }
 
-// Dispatch 路由一条 RPC 请求：先剥离 invokeWithLayer / initConnection /
-// invokeWithoutUpdates / invokeAfter* 等 wrapper（注入 layer / 客户端信息到 ctx），
-// 再按 TypeID 路由到 typed handler。满足 mtprotoedge.RPCHandler。
+// Dispatch routes one RPC and preserves the historical two-value API used by
+// domain/RPC tests. The MTProto edge uses DispatchWithMethod so outbound
+// scheduling sees the canonical inner method rather than an invoke wrapper.
 func (r *Router) Dispatch(ctx context.Context, authKeyID [8]byte, sessionID int64, b *bin.Buffer) (bin.Encoder, error) {
+	enc, _, err := r.DispatchWithMethod(ctx, authKeyID, sessionID, b)
+	return enc, err
+}
+
+// DispatchWithMethod 路由一条 RPC 请求：先剥离 invokeWithLayer / initConnection /
+// invokeWithoutUpdates / invokeAfter* 等 wrapper（注入 layer / 客户端信息到 ctx），
+// 再按 TypeID 路由到 typed handler，并返回 canonical innermost method。
+func (r *Router) DispatchWithMethod(ctx context.Context, authKeyID [8]byte, sessionID int64, b *bin.Buffer) (bin.Encoder, string, error) {
 	preStart := r.clock.Now()
 	ctx = withInboundRPCBytes(ctx, b.Len())
 	ctx = WithRawAuthKeyID(ctx, authKeyID)
 	effectiveAuthKeyID, err := r.effectiveAuthKeyID(ctx, authKeyID, sessionID)
 	if err != nil {
-		return nil, internalErr()
+		return nil, "", internalErr()
 	}
 	tAuth := r.clock.Now()
 	ctx = WithAuthKeyID(ctx, effectiveAuthKeyID)
 	ctx = WithSessionID(ctx, sessionID)
 	userID, hasUserID, err := r.effectiveUserID(ctx, authKeyID, effectiveAuthKeyID, sessionID)
 	if err != nil {
-		return nil, internalErr()
+		return nil, "", internalErr()
 	}
 	if hasUserID {
 		ctx = WithUserID(ctx, userID)
@@ -299,7 +307,9 @@ func (r *Router) Dispatch(ctx context.Context, authKeyID [8]byte, sessionID int6
 			ctx = WithClientInfo(ctx, info.clientInfo)
 		}
 	}
-	return r.dispatch(ctx, b, 0)
+	meta := rpcDispatchMetadata{}
+	enc, err := r.dispatch(ctx, b, 0, &meta)
+	return enc, meta.method, err
 }
 
 func (r *Router) effectiveAuthKeyID(ctx context.Context, rawAuthKeyID [8]byte, sessionID int64) ([8]byte, error) {
@@ -494,7 +504,11 @@ func (r *Router) invalidateAuthUserCache(authKeyID [8]byte) {
 	r.authUserSF.Forget(authKeyClientInfoSingleflightPrefix + key)
 }
 
-func (r *Router) dispatch(ctx context.Context, b *bin.Buffer, depth int) (bin.Encoder, error) {
+type rpcDispatchMetadata struct {
+	method string
+}
+
+func (r *Router) dispatch(ctx context.Context, b *bin.Buffer, depth int, meta *rpcDispatchMetadata) (bin.Encoder, error) {
 	if depth > maxWrapperDepth {
 		return nil, wrapperTooDeepErr()
 	}
@@ -516,13 +530,13 @@ func (r *Router) dispatch(ctx context.Context, b *bin.Buffer, depth int) (bin.En
 		// query 紧跟 layer，buffer 剩余即内层请求。
 		ctx = WithLayer(ctx, layer)
 		r.rememberClientLayer(ctx, layer)
-		return r.dispatch(ctx, b, depth+1)
+		return r.dispatch(ctx, b, depth+1, meta)
 
 	case tg.InvokeWithoutUpdatesRequestTypeID:
 		if err := b.ConsumeID(id); err != nil {
 			return nil, err
 		}
-		return r.dispatch(withInvokeWithoutUpdates(ctx), b, depth+1)
+		return r.dispatch(withInvokeWithoutUpdates(ctx), b, depth+1, meta)
 
 	case tg.InvokeAfterMsgRequestTypeID:
 		if err := b.ConsumeID(id); err != nil {
@@ -531,7 +545,7 @@ func (r *Router) dispatch(ctx context.Context, b *bin.Buffer, depth int) (bin.En
 		if _, err := b.Long(); err != nil {
 			return nil, fmt.Errorf("decode invokeAfterMsg msg_id: %w", err)
 		}
-		return r.dispatch(ctx, b, depth+1)
+		return r.dispatch(ctx, b, depth+1, meta)
 
 	case tg.InvokeAfterMsgsRequestTypeID:
 		if err := b.ConsumeID(id); err != nil {
@@ -549,7 +563,7 @@ func (r *Router) dispatch(ctx context.Context, b *bin.Buffer, depth int) (bin.En
 				return nil, fmt.Errorf("decode invokeAfterMsgs msg_ids[%d]: %w", i, err)
 			}
 		}
-		return r.dispatch(ctx, b, depth+1)
+		return r.dispatch(ctx, b, depth+1, meta)
 
 	case tg.InitConnectionRequestTypeID:
 		req := &tg.InitConnectionRequest{Query: &rawObject{}}
@@ -578,7 +592,7 @@ func (r *Router) dispatch(ctx context.Context, b *bin.Buffer, depth int) (bin.En
 		if !ok {
 			return nil, fmt.Errorf("initConnection query: unexpected type %T", req.Query)
 		}
-		return r.dispatch(ctx, &bin.Buffer{Buf: inner.data}, depth+1)
+		return r.dispatch(ctx, &bin.Buffer{Buf: inner.data}, depth+1, meta)
 
 	default:
 		// 入站兼容统一入口（先于鉴权门/dispatcher）：layerwire 把老客户端请求升级为
@@ -606,6 +620,9 @@ func (r *Router) dispatch(ctx context.Context, b *bin.Buffer, depth int) (bin.En
 				}
 			}
 		}
+		if meta != nil {
+			meta.method = tlTypeName(id)
+		}
 		knownRequest, structuralErr := layerwire.ValidateRoutableRequest(b.Buf)
 		if !knownRequest {
 			if structuralErr != nil {
@@ -834,6 +851,37 @@ func (r *Router) NegotiatedLayer(authKeyID [8]byte, sessionID int64) (int, bool)
 	return currentClientLayer, false
 }
 
+// ObserveInitConnection records the protocol metadata of an initConnection
+// whose inner request was aliased by mtprotoedge to an already-running naked
+// request. It deliberately performs no handler dispatch and therefore cannot
+// repeat business side effects.
+func (r *Router) ObserveInitConnection(
+	ctx context.Context,
+	rawAuthKeyID [8]byte,
+	sessionID int64,
+	layer, apiID int,
+	deviceModel, systemVersion, appVersion, systemLangCode, langPack, langCode string,
+) error {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	ctx = WithRawAuthKeyID(ctx, rawAuthKeyID)
+	effectiveAuthKeyID, err := r.effectiveAuthKeyID(ctx, rawAuthKeyID, sessionID)
+	if err != nil {
+		return err
+	}
+	ctx = WithAuthKeyID(ctx, effectiveAuthKeyID)
+	ctx = WithSessionID(ctx, sessionID)
+	ctx = WithLayer(ctx, layer)
+	r.rememberClientLayer(ctx, layer)
+	r.rememberClientInfo(ctx, ClientInfo{
+		APIID: apiID, DeviceModel: deviceModel, SystemVersion: systemVersion,
+		AppVersion: appVersion, SystemLangCode: systemLangCode,
+		LangPack: langPack, LangCode: langCode,
+	})
+	return nil
+}
+
 // mutateClientSessionInfo 在单个临界区内完成「读旧值-修改-写回」，避免
 // RLock 读出与 Lock 写回之间被并发写覆盖的窗口。
 func (r *Router) mutateClientSessionInfo(ctx context.Context, mutate func(*clientSessionInfo)) {

internal/rpc/router_dispatch_test.go

@@ -49,10 +49,13 @@ func TestDispatchUnwrapsWrappers(t *testing.T) {
 		t.Fatalf("encode wrapped request: %v", err)
 	}
 
-	enc, err := r.Dispatch(context.Background(), [8]byte{}, 0, &b)
+	enc, method, err := r.DispatchWithMethod(context.Background(), [8]byte{}, 0, &b)
 	if err != nil {
 		t.Fatalf("dispatch: %v", err)
 	}
+	if method != "help.getConfig" {
+		t.Fatalf("effective method = %q, want help.getConfig", method)
+	}
 	cfg, ok := enc.(*tg.Config)
 	if !ok {
 		t.Fatalf("result type = %T, want *tg.Config", enc)