*   <li>After processing a URL ({@link #delayAfterProcessing()})</li>
 *   <li>When there are no URLs in the queue ({@link #delayAtNoUrlInQueue()})</li>
 *   <li>While waiting for new URLs to be added to the queue ({@link #delayForWaitingNewUrl()})</li>
 * </ul>
 *
 * <p>
 * Subclasses are responsible for implementing the abstract methods to define the actual delay
 * mechanism for each of these stages.
 * </p>
 *
 * <p>

     * This method calibrates CPU load, checks crawler status, applies
     * interval control rules, and then calls the parent implementation.
     */
    @Override
    protected void delayForWaitingNewUrl() {
        ComponentUtil.getSystemHelper().calibrateCpuLoad();
        try {
            final IntervalControlHelper intervalControlHelper = ComponentUtil.getIntervalControlHelper();

            ThreadUtil.sleep(delayMillisBeforeProcessing);
        }
    }

    /**
     * Delays for waiting for new URLs.
     */
    @Override
    protected void delayForWaitingNewUrl() {
        if (delayMillisForWaitingNewUrl > 0) {
            ThreadUtil.sleep(delayMillisForWaitingNewUrl);
        }
    }