feat: custom response format

pkg/resolvers/resolver.go

@@ -1,10 +1,23 @@
 package resolvers
 
-import "github.com/miekg/dns"
+import (
+	"time"
+
+	"github.com/miekg/dns"
+)
 
 // Resolver implements the configuration for a DNS
 // Client. Different types of client like (UDP/TCP/DOH/DOT)
 // can be initialised.
 type Resolver interface {
-	Lookup([]dns.Question) error
+	Lookup([]dns.Question) ([]Response, error)
+}
+
+// Response represents a custom output format
+// which wraps certain metadata about the DNS query
+// and the DNS Answer as well.
+type Response struct {
+	Message    dns.Msg
+	RTT        time.Duration
+	Nameserver string
 }