code: @Override
      public void serverStopping() {
          deactivated = true;
          Future<?> pollingFuture = pollingFutureRef.get();
          if (pollingFuture != null)
              pollingFuture.cancel(false);
      }
docs: Invoked when the server is stopped without the {@code --force}.
  This gives us an opportunity to stop polling for tasks to run
  and mark ourselves as deactivated so that we don't start any new tasks.
  
  @see com.ibm.wsspi.kernel.service.utils.ServerQuiesceListener#serverStopping()