code: func (mux *Multiplexer) stopConsuming(topic string, name string) error {
  	mux.rwlock.Lock()
  	defer mux.rwlock.Unlock()
  
  	var wasError error
  	var topicFound bool
  	for index, subs := range mux.mapping {
  		if !subs.manual && subs.topic == topic && subs.connectionName == name {
  			topicFound = true
  			mux.mapping = append(mux.mapping[:index], mux.mapping[index+1:]...)
  		}
  	}
  	if !topicFound {
  		wasError = fmt.Errorf("topic %s was not consumed by '%s'", topic, name)
  	}
  	return wasError
  }
docs: // Remove consumer subscription on given topic. If there is no such a subscription, return error.