docs: protected AsyncResponseImpl checkFutureResponse(Message inMessage, Object result) {
          if (result instanceof CompletionStage) {
              final CompletionStage<?> stage = (CompletionStage<?>)result;
              final AsyncResponseImpl asyncResponse = new AsyncResponseImpl(inMessage);
              stage.whenComplete((v, t) -> {
                  if (t instanceof CancellationException) {
                      asyncResponse.cancel();
                  } else {
                      asyncResponse.resume(v != null ? v : t);
                  }
              });
              return asyncResponse;
          }
          return null;
      }