Xamarin Forms Marshmallow Permissions

Hi,
I am trying to ask for location permission on Android 6 through the DependencyService. My problem is that I do not know how to handle the callback of the ActivityCompat.RequestPermissions (activity, permissionGroup, permissionRequestID);

I tried to follow this and this but since I do not have a class for the activity I can not use OnRequestPermissionsResult. A solution I tried was to extend the activity object at runtime but using ActivityCompat.IOnRequestPermissionsResultCallback says there is no override for OnRequestPermissionsResult