Move channel setup to a separate startNotify helper

Also add a very small buffer to the NotifyReturn channel
in case no one is listening on the other side.

I event thought about actually having a timeout when sending
to that channel, but it felt it could lead to loss of
events on non problematic situations, so let's see how this
works instead.

publish.go

@@ -155,22 +155,10 @@ func NewPublisher(url string, config amqp.Config, optionFuncs ...func(*Publisher
 
 	returnChan := make(chan Return)
 	go func() {
-		setupNotifyChans := func() {
-			returnAMQPChan := publisher.chManager.channel.NotifyReturn(make(chan amqp.Return))
-			go func() {
-				for ret := range returnAMQPChan {
-					returnChan <- Return{ret}
-				}
-			}()
-
-			notifyFlowChan := publisher.chManager.channel.NotifyFlow(make(chan bool))
-			go publisher.startNotifyFlowHandler(notifyFlowChan)
-		}
-
-		setupNotifyChans()
+		publisher.startNotifyHandlers(returnChan)
 		for err := range publisher.chManager.notifyCancelOrClose {
 			publisher.logger.Printf("publish cancel/close handler triggered. err: %v", err)
-			setupNotifyChans()
+			publisher.startNotifyHandlers(returnChan)
 		}
 	}()
 
@@ -227,6 +215,18 @@ func (publisher Publisher) StopPublishing() {
 	publisher.chManager.connection.Close()
 }
 
+func (publisher *Publisher) startNotifyHandlers(returnChan chan Return) {
+	returnAMQPChan := publisher.chManager.channel.NotifyReturn(make(chan amqp.Return, 1))
+	go func() {
+		for ret := range returnAMQPChan {
+			returnChan <- Return{ret}
+		}
+	}()
+
+	notifyFlowChan := publisher.chManager.channel.NotifyFlow(make(chan bool))
+	go publisher.startNotifyFlowHandler(notifyFlowChan)
+}
+
 func (publisher *Publisher) startNotifyFlowHandler(notifyFlowChan chan bool) {
 	// Listeners for active=true flow control.  When true is sent to a listener,
 	// publishing should pause until false is sent to listeners.