No data returned when calling Graph API

Im currently using the curl-multi module for parallel http-request, calling facebook's api. I want to replace the curl-multi with the htttprl-module, but cant really figure out, where the return data is located:

httprl_request('https://graph.facebook.com/postid/insights?access_token=token');
// Execute request.
$request = httprl_send_request();
dpm($request);

The $request-data is empty, so Im wondering, where the insights-data is?