public function send()
    {
        if (headers_sent()) {
            return false;
        }
        // set headers
        foreach ($this->getHeaders() as $h) {
            header($h[0] . ': ' . $h[1], false, $this->_statusCode);
        }
        // set status code
        if (function_exists('http_response_code')) {
            http_response_code($this->_statusCode);
        }
        // send content
        echo $this->_content;
        return true;
    }