anchor.diff:          }
       }
   
  +    /// Return the number of listeners for a given event.
       static int listenerCount(EventEmitter emitter, event) {
           return emitter.listeners(event).length;
       }
  
positive.code:         }
      }
  
      EventEmitter removeListener(event, listener) {
          if (_listeners.containsKey(event) && _listeners[event].contains(listener)) {
              _listeners[event].remove(listener);
  
negative.code: part 'src/events/new_listener_event.dart';
  part 'src/events/remove_listener_event.dart';
  
  /// The look of handler function that can be executed when adding an [EventInterface] event
  typedef void EventHandlerFunction(EventInterface event);
  
  /// EventEmitter class
  class EventEmitter {
      /// Method [setMaxListeners] sets the maximum on a per-instance basis.
      /// This class property lets you set it for all [EventEmitter] instances, current and future, effective immediately. Use with care.
      /// Note that [setMaxListeners] still has precedence over [defaultMaxListeners].
      static int defaultMaxListeners = 10;
  
      Map<dynamic, List> _listeners = {};
      Map<dynamic, List> _oneTimeListeners = {};
      int _maxListeners;
  
      /// Adds a listener to the end of the listeners array for the specified event.
      /// No checks are made to see if the listener has already been added.
      /// Multiple calls passing the same combination of event and listener will result in the listener being added multiple times.
      /// You can pass [String] or [EventInterface] object **Type** as event.
      /// Listener can be either simple function or [EventHandlerInterface] object
      EventEmitter addListener(event, listener) {
          if (!_listeners.containsKey(event)) {
              _listeners[event] = [];
  