protected final Queue<Map<String, Object>> queue = new ConcurrentLinkedQueue<>();
    /** Flag indicating if reading is finished. */
    protected final AtomicBoolean isFinished = new AtomicBoolean(false);
    /** Random number generator. */
    protected final Random random = new Random();

    /** OpenSearch client. */
    protected final Client client;
    /** Suggest settings. */
    protected final SuggestSettings settings;