childUrlSet.add(url);
    }

    /**
     * Removes a child URL from this response.
     *
     * @param url the child URL to remove
     */
    public void removeChildUrl(final RequestData url) {
        childUrlSet.remove(url);
    }

    /**
     * Gets the set of child URLs discovered from this response.
     *
     * @return the set of child URLs
     */