request.
Note:
 the type of "worker_id" is implementation specific. It is
 whatever the TimerServer and TimerClient implementations have on
 to uniquely identify a worker.

class torch.distributed.elastic.timer.TimerServer(request_queue, max_interval, daemon=True)
Entity that monitors active timers and expires them in a timely
   fashion. This server is responsible for reaping workers that have
   expired timers.
abstract clear_timers(worker_ids)
  Clears all timers for the given "worker_ids".

abstract get_expired_timers(deadline)
  Returns all expired timers for each worker_id. An expired timer
  is a timer for which the expiration_time is less than or equal
  to the provided deadline.

  Return type:
     *Dict*[str, *List*[*TimerRequest*]]

abstract register_timers(timer_requests)
  Processes the incoming timer requests and registers them with
  the server. The timer request can either be a acquire-timer or
