protected function sendGetContent($url, $security = null)
    {
        // sign url if security is passed in
        if ($security) {
            $url = $security->signUrl($url);
        }

        $response = $this->sendRequest('GET', $url);
        $status_code = $response->getStatusCode();

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

        $content = $response->getBody()->getContents();

        return $content;
    }