Merge pull request #135 from mschneider82/master

close channel only once. fixes panic #134

subscription.go

@@ -30,6 +30,7 @@ type Subscription struct {
 	state                     int32
 	closeMutex                *sync.Mutex
 	closeCond                 *sync.Cond
+	closeOnce                 sync.Once
 	unsubscribeReceiptTimeout time.Duration
 }
 
@@ -146,12 +147,14 @@ func (s *Subscription) Read() (*Message, error) {
 }
 
 func (s *Subscription) closeChannel(msg *Message) {
-	if msg != nil {
-		s.C <- msg
-	}
-	atomic.StoreInt32(&s.state, subStateClosed)
-	close(s.C)
-	s.closeCond.Broadcast()
+	s.closeOnce.Do(func() {
+		if msg != nil {
+			s.C <- msg
+		}
+		atomic.StoreInt32(&s.state, subStateClosed)
+		close(s.C)
+		s.closeCond.Broadcast()
+	})
 }
 
 func (s *Subscription) subscriptionErrorMessage(message string) *Message {