/**
     * QueueHolder holds the waiting and crawling queues.
     */
    protected static class QueueHolder {
        /**
         * Constructs a new QueueHolder.
         */
        public QueueHolder() {
            // Default constructor
        }

        /**
         * The queue for URLs waiting to be crawled.
         */
        protected Queue<OpenSearchUrlQueue> waitingQueue = new ConcurrentLinkedQueue<>();

        return true;
    }

    /**
     * Stores child URLs from the given set into the crawling queue for future processing.
     * This method filters out blank URLs and increments the depth for child URLs.
     *
     * @param urlQueue the parent URL queue item
     * @param childUrlSet the set of child URLs to be queued for crawling
     */

            CopyUtil.copy(in, out);
            asyncImport(fileName, tempFile);

            if (logger.isInfoEnabled()) {
                logger.info("Backup file uploaded successfully and queued for import: fileName={}, tempFile={}", fileName,
                        tempFile.getAbsolutePath());
            }
        } catch (final IOException e) {

 *  Fix: Handle multiple 1xx responses.

 *  Fix: Address a performance bug in our internal task runner. We had a race condition that could
    result in it OkHttp starting a thread for each queued task, even when a single thread could run
    all of them.

 *  Fix: Address a performance bug in `MultipartReader`. We were scanning the entire input stream

            if ("https://example.com/page1".equals(queue.getUrl())) {
                foundPage1 = true;
                assertEquals("GET", queue.getMethod());
                assertEquals("https://example.com", queue.getParentUrl());
                assertEquals(Long.valueOf(123456789L), queue.getLastModified());
            } else if ("https://example.com/page2".equals(queue.getUrl())) {
                foundPage2 = true;

  @Nullable FinalizableWeakReference<Object> reference;

  /** Create the FRQ in a method that goes out of scope so that we're sure it will be reclaimed. */
  private void weaklyReferenceQueue() {
    frq = new FinalizableReferenceQueue();
    queueReference = new WeakReference<>(frq.queue);

    /*
     * Queue and clear a reference for good measure. We test later on that

            finishedSessionIdList.add(sessionId);
        }
    }

    /**
     * Deletes all data associated with a specific crawler session.
     * Removes URL filters, URL queues, and access result data for the session.
     *
     * @param sessionId the session ID whose data should be deleted
     */
    private void deleteBySessionId(final String sessionId) {
        try {

    }

    /**
     * Adds a URL to the crawling queue.
     * @param url The URL to add.
     */
    public void addUrl(final String url) {
        try {
            urlQueueService.add(crawlerContext.sessionId, url);
            if (logger.isDebugEnabled()) {
                logger.debug("Added URL to queue: url={}, sessionId={}", url, crawlerContext.sessionId);
            }

   *
   * <p>Note: If {@code iterable} is a {@link Queue}, the returned iterable will instead use {@link
   * Queue#isEmpty} and {@link Queue#remove()}, since {@link Queue}'s iteration order is undefined.
   * Calling {@link Iterator#hasNext()} on a generated iterator from the returned iterable may cause
   * an item to be immediately dequeued for return on a subsequent call to {@link Iterator#next()}.
   *

        UrlQueueImpl<Long> queue = new UrlQueueImpl<>();
        assertNotNull(queue);
        assertNull(queue.getId());
        assertNull(queue.getSessionId());
        assertNull(queue.getMethod());
        assertNull(queue.getUrl());
        assertNull(queue.getMetaData());
        assertNull(queue.getEncoding());
        assertNull(queue.getParentUrl());
        assertNull(queue.getDepth());