data.addChildUrl(child1);
        data.addChildUrl(child2);
        assertEquals(2, data.getChildUrlSet().size());

        // Remove one child URL
        data.removeChildUrl(child1);
        assertEquals(1, data.getChildUrlSet().size());
        assertFalse(data.getChildUrlSet().contains(child1));
        assertTrue(data.getChildUrlSet().contains(child2));
    }

        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
     */