code: func (fb *Firebase) RemoveEventFunc(fn ChildEventFunc) {
  	fb.eventMtx.Lock()
  	defer fb.eventMtx.Unlock()
  
  	key := fmt.Sprintf("%v", fn)
  	stop, ok := fb.eventFuncs[key]
  	if !ok {
  		return
  	}
  
  	delete(fb.eventFuncs, key)
  	close(stop)
  }
docs: // RemoveEventFunc removes the given function from the firebase
  // reference.