* </p>
 * <ul>
 *   <li>Before processing a URL ({@link #delayBeforeProcessing()})</li>
 *   <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>

        if (millis != null) {
            delayMillisForWaitingNewUrl = millis;
        }

    }

    /**
     * Delays after processing a URL.
     */
    @Override
    protected void delayAfterProcessing() {
        if (delayMillisAfterProcessing > 0) {
            ThreadUtil.sleep(delayMillisAfterProcessing);
        }
    }

    /**
     * Delays when no URL is in the queue.
     */
    @Override

        @Override
        public void delay(int type) {
        }

        public void delayBeforeProcessing() {
        }

        public void delayAfterProcessing() {
        }

        public void delayAtNoUrlInQueue() {
        }

        public void delayForWaitingNewUrl() {
        }
    }

    /**
     * Test default constructor