code: public boolean removeMessageListener(String topic, IKafkaMessageListener msgListener) {
          synchronized (topicMsgListeners) {
              if (topicMsgListeners.remove(topic, msgListener)) {
                  if (topicMsgListeners.get(topic).isEmpty()) {
                      // no more listener, stop worker
                      KafkaMsgConsumerWorker worker = topicWorkers.remove(topic);
                      if (worker != null) {
                          worker.stopWorker();
                      }
                  }
                  return true;
              }
          }
          return false;
      }
docs: Removes a topic message listener.
  
  @param topic
  @param msgListener
  @return {@code true} if successful, {@code false} otherwise (the topic
  may have no such listener added before)