/** Sort list. */
    protected List<SortBuilder<?>> sortList = new ArrayList<>();

    /** Scroll ID. */
    protected String scrollId = null;

    /** Document count. */
    protected final AtomicLong docCount = new AtomicLong(0);
    /** Total document number. */
    protected final long totalDocNum;

    /**
     * Constructor for ESSourceReader.
     * @param client The OpenSearch client.

        try {
            final URI uri = new URI(url);
            final String host = uri.getHost();
            if (host == null) {
                return;
            }
            final AtomicLong lastTime = lastTimes.putIfAbsent(host, new AtomicLong(SystemUtil.currentTimeMillis()));
            if (lastTime == null) {
                return;
            }
            synchronized (lastTime) {
                while (true) {

     */
    protected Object activeThreadCountLock = new Object();

    /**
     * Atomic counter for tracking the number of accesses made.
     */
    protected AtomicLong accessCount = new AtomicLong(0);

    /**
     * Current status of the crawler.
     */
    protected volatile CrawlerStatus status = CrawlerStatus.INITIALIZING;

    /**