docs: private void scheduleClockUpdating() {
  		ScheduledExecutorService scheduler = Executors.newSingleThreadScheduledExecutor(new ThreadFactory(){
  			@Override
  			public Thread newThread(Runnable runnable) {
  				Thread thread = new Thread(runnable, "System Clock");
  				thread.setDaemon(true);
  				return thread;
  			}
  		});
  		scheduler.scheduleAtFixedRate(new Runnable(){
  			@Override
  			public void run() {
  				now = System.currentTimeMillis();
  			}
  		}, period, period, TimeUnit.MILLISECONDS);
  	}