code: func (ref *Consumer) notificationHandler(in <-chan *cluster.Notification) {
  	ref.Debug("NotificationHandler started ...")
  
  	for {
  		select {
  		case note := <-in:
  			ref.Config.RecvNotificationChan <- note
  		case <-ref.closeChannel:
  			ref.Debug("Canceling notification handler")
  			return
  		}
  	}
  }
docs: // NotificationHandler processes each message received when the consumer is rebalanced