emit method
Call all listeners registered for eventName event
All listeners found are called with positionalArguments
and namedArguments
Listeners registered as once is then cleared
Implementation
@mustCallSuper
bool emit(
  String eventName, [
  List? positionalArguments,
  Map<Symbol, dynamic>? namedArguments,
]) {
  assert(eventName.isNotEmpty);
  if (!_events.containsKey(eventName)) {
    return false;
  }
  final _listeners = listeners(eventName)!;
  final _onceListeners = <_KuzzleListener>[];
  for (final listener in _listeners) {
    if (listener.once!) {
      _onceListeners.add(listener);
    }
    try {
      Function.apply(listener.fn, positionalArguments, namedArguments);
    } on Exception {
      print('$runtimeType.emit($eventName) => listener.fn errored');
      print('Did the listener was registered correctly?');
    }
  }
  for (final listener in _onceListeners) {
    removeListener(eventName, listener.fn);
  }
  return true;
}