latch.countDown();
    }

    public Promise then(final Consumer<RESPONSE> consumer) {
        return promise.then(consumer);
    }

    public Promise error(final Consumer<Throwable> consumer) {
        return promise.error(consumer);
    }

    public Promise promise() {
        return promise;
    }

    public class Promise {
        public Promise then(final Consumer<RESPONSE> consumer) {

            deferred.resolve(new SuggestResponse("", 0, Collections.emptyList(), 0, null));
        });
        th.start();

        final CountDownLatch latch = new CountDownLatch(1);
        deferred.promise().then(response -> latch.countDown());
        assertTrue(latch.await(10, TimeUnit.SECONDS));
    }

    @Test
    public void test_doneAfterResolve() throws Exception {

import org.codelibs.fess.suggest.exception.SuggesterException;
import org.opensearch.client.Client;
import org.opensearch.core.common.Strings;

public abstract class Request<T extends Response> {
    public Deferred<T>.Promise execute(final Client client) {
        final String error = getValidationError();
        if (!Strings.isNullOrEmpty(error)) {
            throw new IllegalArgumentException(error);
        }

    val request =
      Request.Builder()
        .url(url)
        .build()

    val promise = CompletableFuture<Response>()

    val call = client.newCall(request)
    call.enqueue(
      object : Callback {
        override fun onFailure(
          call: Call,
          e: IOException,
        ) {
          promise.completeExceptionally(e)
        }

        override fun onResponse(

    headersDelayAmount = delay
    headersDelayUnit = unit
  }

  fun getHeadersDelay(unit: TimeUnit): Long = unit.convert(headersDelayAmount, headersDelayUnit)

  fun withPush(promise: PushPromise) =
    apply {
      promises.add(promise)
    }

  fun withSettings(settings: Settings) =
    apply {
      this.settings = settings
    }

  fun withWebSocketUpgrade(listener: WebSocketListener) =

        }
    }

    @Deprecated
    public Deferred<SuggestIndexResponse>.Promise indexFromDocument(final Supplier<DocumentReader> reader, final int docPerReq,
            final long requestInterval) {
        return indexFromDocument(reader, docPerReq, () -> ThreadUtil.sleep(requestInterval));
    }

    public Deferred<SuggestIndexResponse>.Promise indexFromDocument(final Supplier<DocumentReader> reader, final int docPerReq,

       * we're copying into a `contents` array whose type allows it to contain nulls. Still, it's
       * worth noting that we promise not to put nulls into the array in the first `size` elements.
       * We uphold that promise here because our callers promise that `elements` will not contain
       * nulls in its first `n` elements.
       */
      System.arraycopy(elements, 0, contents, size, n);
      size += n;

        flags = FLAG_ACK,
      )
      sink.flush()
    }
  }

  /**
   * HTTP/2 only. Send a push promise header block.
   *
   * A push promise contains all the headers that pertain to a server-initiated request, and a
   * `promisedStreamId` to which response frames will be delivered. Push promise frames are sent as
   * a part of the response to `streamId`. The `promisedStreamId` has a priority of one greater than

    protected Req request;

    public RequestBuilder(final Client client, final Req request) {
        this.client = client;
        this.request = request;
    }

    public Deferred<Res>.Promise execute() {
        return request.execute(client);
    }

      weight: Int,
      exclusive: Boolean,
    )

    /**
     * HTTP/2 only. Receive a push promise header block.
     *
     * A push promise contains all the headers that pertain to a server-initiated request, and a
     * `promisedStreamId` to which response frames will be delivered. Push promise frames are sent
     * as a part of the response to `streamId`.
     *