final CrawlerClientFactory crawlerClientFactory =
                config.initializeClientFactory(() -> ComponentUtil.getComponent(CrawlerClientFactory.class));
        final CrawlerClient client = crawlerClientFactory.getClient(url);
        if (client == null) {
            throw new FessSystemException("No CrawlerClient: " + configId + ", url: " + url);
        }
        return writeContent(configId, url, client);
    }

    /**

   * that we have to flush headers immediately before any request body can be sent.
   * https://github.com/square/okhttp/issues/2543
   */
  @Test fun peerSetsZeroFlowControl() {
    peer.setClient(true)

    // Write the mocking script.
    peer.sendFrame().settings(Settings().set(Settings.INITIAL_WINDOW_SIZE, 0))
    peer.acceptFrame() // ACK