code: public static ScheduledExecutorService createScheduler() {
  		final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1, new DaemonThreadFactory(DEFAULT_SCHEDULER_NAME));
  		SCHEDULERS.add(scheduler);
  		return scheduler;
  	}
docs: Creates a single-threaded scheduler that is registered by this class in order to shut it down later (when it
  becomes necessary).
  
  @return a new scheduler