public function sendDebug($transform_url, $api_key, $security = null)
    {
        $transform_str = str_replace(FilestackConfig::CDN_URL . '/', '', $transform_url);
        $debug_url = sprintf('%s/%s/debug/%s', FilestackConfig::CDN_URL,
            $api_key, $transform_str);

        if ($security) {
            $debug_url = $security->signUrl($debug_url);
        }

        // call CommonMixin function
        $response = $this->sendRequest('GET', $debug_url);
        $status_code = $response->getStatusCode();

        // handle response
        if ($status_code !== 200) {
            throw new FilestackException($response->getBody(), $status_code);
        }

        $json_response = json_decode($response->getBody(), true);

        return $json_response;
    }