Close audio streams when listeners detach

gumble/gumble/audiolisteners.go

@@ -17,6 +17,10 @@ func (e *audioEventItem) Detach() {
 		return
 	}
 	e.detached = true
+	for user, stream := range e.streams {
+		close(stream)
+		delete(e.streams, user)
+	}
 	if e.prev == nil {
 		e.parent.head = e.next
 	} else {

gumble/gumble/listeners_regression_test.go

@@ -28,8 +28,13 @@ func TestListenerDetachIsIdempotentAndConcurrent(t *testing.T) {
 func TestAudioListenerDetachIsIdempotent(t *testing.T) {
 	var listeners AudioListeners
 	item := listeners.Attach(nil)
+	stream := make(chan *AudioPacket)
+	item.(*audioEventItem).streams[&User{}] = stream
 	item.Detach()
 	item.Detach()
+	if _, open := <-stream; open {
+		t.Fatal("detached audio listener stream remained open")
+	}
 	listeners.mu.Lock()
 	defer listeners.mu.Unlock()
 	if listeners.head != nil || listeners.tail != nil {