code: public static ExecutorService createBackgroundExecutor() {
  		final ExecutorService executor = Executors.newSingleThreadExecutor(new DaemonThreadFactory(DEFAULT_BACKGROUND_EXECUTOR_NAME));
  		BACKGROUND_EXECUTORS.add(executor);
  		return executor;
  	}
docs: Creates a single-threaded executor that is registered by this class in order to shut it down later (when it
  becomes necessary).
  
  @return a new background executor