public function append($url = '', $argsOrParams = array(), $params = array())
    {
        if (strpos($url, '%s') !== false) {
            $url = vsprintf($url, (array)$argsOrParams);
        } else {
            $params = $argsOrParams;
        }
        if ($params) {
            $url .= (false === strpos($url, '?') ? '?' : '&');
        }
        return $url . (is_array($params) ? http_build_query($params) : $params);
    }