added StopReceivingUpdates to stop updates routine

There was no way to stop the bot from fetching updates, Added StopReceivingUpdates() so we can stop updates when we are done with bot.

bot.go

@@ -28,6 +28,7 @@ type BotAPI struct {
 
 	Self   User         `json:"-"`
 	Client *http.Client `json:"-"`
+	shutdownChannel chan interface{}
 }
 
 // NewBotAPI creates a new BotAPI instance.
@@ -46,6 +47,7 @@ func NewBotAPIWithClient(token string, client *http.Client) (*BotAPI, error) {
 		Token:  token,
 		Client: client,
 		Buffer: 100,
+		shutdownChannel: make(chan interface{}),
 	}
 
 	self, err := bot.GetMe()
@@ -480,6 +482,12 @@ func (bot *BotAPI) GetUpdatesChan(config UpdateConfig) (UpdatesChannel, error) {
 
 	go func() {
 		for {
+			select {
+			case <-bot.shutdownChannel:
+				return
+			default:
+			}
+			
 			updates, err := bot.GetUpdates(config)
 			if err != nil {
 				log.Println(err)
@@ -501,6 +509,14 @@ func (bot *BotAPI) GetUpdatesChan(config UpdateConfig) (UpdatesChannel, error) {
 	return ch, nil
 }
 
+// StopReceivingUpdates stops the go routine which receives updates
+func (bot *BotAPI) StopReceivingUpdates() {
+	if bot.Debug {
+		log.Println("Stopping the update receiver routine...")
+	}
+	close(bot.shutdownChannel)
+}
+
 // ListenForWebhook registers a http handler for a webhook.
 func (bot *BotAPI) ListenForWebhook(pattern string) UpdatesChannel {
 	ch := make(chan Update, bot.Buffer)