code: @Beta
    public Future<HttpResponse> executeAsync(Executor executor) {
      FutureTask<HttpResponse> future =
          new FutureTask<HttpResponse>(
              new Callable<HttpResponse>() {
  
                public HttpResponse call() throws Exception {
                  return execute();
                }
              });
      executor.execute(future);
      return future;
    }
docs: {@link Beta} <br>
  Executes this request asynchronously in a single separate thread using the supplied executor.
  
  @param executor executor to run the asynchronous request
  @return future for accessing the HTTP response
  @since 1.13