stop method Null safety

void stop()

stop and remove all remain jobs in queue

would be useful if want to stop the queue when a job fails

Implementation

void stop() {
  _isForcedClosed = true;
  _isRunning = false;
  _first = null;
  _last = null;
  _size = 0;
  _emitEvent(QueueEventType.queueStopped);
}