public function post(string $url, $data, array $headers = [])
    {
        if (is_array($data)) {
            $headers['Content-type'] = self::FORM_CONTENT_TYPE;
        }

        $ctx = $this->getContext('POST', $data, $headers);
        $response = file_get_contents($url, false, $ctx);
        $this->saveCookies($http_response_header);

        return $response;
    }