code: @SuppressWarnings("unchecked")
      @Override
      protected InvocationCallback<Object> checkAsyncCallback(OperationResourceInfo ori,
                                                              Map<String, Object> reqContext,
                                                              Message outMessage) {
          InvocationCallback<Object> callback = outMessage.getContent(InvocationCallback.class);
          if (callback == null && CompletionStage.class.equals(ori.getMethodToInvoke().getReturnType())) {
              callback = NO_OP_CALLBACK;
              outMessage.setContent(InvocationCallback.class, callback);
          }
          return callback;
      }
docs: Liberty change end