title: Wait until all event listeners done
body: <p>So once called, an event emitter loses any control of what event listeners are doing and how long they will run.  But what if we need to do next thing only after all event listeners complete they work?  How can I know when they have completed their work?</p>
  
  <p>One solution could be to get listeners from EventEmitter.listeners() and call them in parallel with async or something like this, but this is not that great at all. ((</p>
  
  <p>Any nice solution for this?</p>