code: public static void releaseSharedResources(long timeout, TimeUnit unit) throws InterruptedException {
          sharedExecutor().awaitTermination(timeout, unit);
          sharedEventLoop().shutdownGracefully().await(timeout, unit);
          sharedWheelTimer().stop();
      }
docs: Shutdown/stop any shared resources that me be in use, blocking until finished or interrupted.
  
  @param timeout the duration to wait.
  @param unit    the {@link TimeUnit} of the {@code timeout} duration.