public function render($view = null, $layout = null)
    {
        $serialize = false;
        if (isset($this->viewVars['_serialize'])) {
            $serialize = $this->viewVars['_serialize'];
        }

        if ($serialize !== false) {
            $result = $this->_serialize($serialize);
            if ($result === false) {
                throw new RuntimeException('Serialization of View data failed.');
            }

            return (string)$result;
        }
        if ($view !== false && $this->_getViewFileName($view)) {
            return parent::render($view, false);
        }
    }