code: func (q *Queue) Notify(mask EventMask) {
  	q.mu.RLock()
  	for e := q.list.Front(); e != nil; e = e.Next() {
  		if mask&e.mask != 0 {
  			e.Callback.Callback(e)
  		}
  	}
  	q.mu.RUnlock()
  }
docs: // Notify notifies all waiters in the queue whose masks have at least one bit
  // in common with the notification mask.