public function sendRtf($filename = 'simple', $free = true)
    {
        $pathInfo = pathinfo($filename);

        if (empty($pathInfo['extension'])) {
            $filename .= '.rtf';
        }

        if (false !== strpos($_SERVER['HTTP_USER_AGENT'], 'MSIE 5.5')) {
            header('Content-Disposition: filename="' . $filename . '"');
        }
        else {
            header('Content-Disposition: attachment; filename="' . $filename . '"');
        }
        header('Content-type: application/msword');
        header('Expires: 0');
        header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
        header('Pragma: public');

        $this->createWriter();
        $this->render();

        if ($free) {
            $this->free();
        }

        echo $this->_writer->getContent();
    }