protected function _setStatus($code, $reasonPhrase = '')
    {
        if (!isset($this->_statusCodes[$code])) {
            throw new InvalidArgumentException(sprintf(
                'Invalid status code: %s. Use a valid HTTP status code in range 1xx - 5xx.',
                $code
            ));
        }

        $this->_status = $code;
        if (empty($reasonPhrase)) {
            $reasonPhrase = $this->_statusCodes[$code];
        }
        $this->_reasonPhrase = $reasonPhrase;
        $this->_setContentType();
    }