anchor.diff:          return result;
       }
   
  -    void emit(String event) {
  +    bool emit(String event) {
  +        bool handlersFound = false;
  +
           if (_listeners.containsKey(event)) {
  +            handlersFound = true;
               _listeners[event].forEach((Function handler) {
                   handler();
               });
           }
   
           if (_oneTimeListeners.containsKey(event)) {
  +            handlersFound = true;
               for (int i = 0; i < _oneTimeListeners[event].length; i++) {
                   Function handler = _oneTimeListeners[event][i];
                   handler();
                   _oneTimeListeners[event].removeAt(i);
               }
           }
  +
  +        return handlersFound;
       }
   
       static int listenerCount(EventEmitterInterface emitter, String event) {
  
positive.code:                 _oneTimeListeners[event].clear();
              }
          }
      }
  
      void setMaxListeners(int listenersCount) {
          _maxListeners = listenersCount;
      }
  
      List listeners(String event) {
  
negative.code:         return _maxListeners;
      }
  
      void _verifyListenersLimit(String event) {
          int nextCount = ++listeners(event).length;
          int maxListeners = _getMaxListeners();
  
  