private function debugRequest($url, array $headers, $body)
    {
        $str = $url.PHP_EOL;

        $str .= array_reduce(array_keys($headers), function ($str, $key) use ($headers) {
            $str .= $key.': '.$headers[$key].PHP_EOL;
            return $str;
        }, '');

        $str .= $body;

        $this->debug($str);
    }