code: @Deprecated
  	public void addShutdownHook(final Runnable runnable) {
  		closeables.offer(new AutoCloseable() {
  			@Override
  			public void close() {
  				runnable.run();
  			}
  		});
  	}
docs: Add a {@link Runnable} (NOT the JVM's <i>shutdown hook</i>) into the queue
  which will be run when the service is stopping.
  
  @deprecated use {@link #register(AutoCloseable)} instead