Detect media capture on hololens

Hi,

I need to detect if the Hololens captures a photo or a video, in order to start some post-processing steps.

I tried using AppCapture.GetForCurrentView().CapturingChanged as suggested in this post, but it doesn't work. The event listener method is never called.

Is there are way to get the volume button presses in Unity? That way I could at least "assume" that a photo or video has been taken.

The other option would be to check the Camera Roll folder for new files all the time, and do something if a new file appears. But that doesn't feel really elegant or efficient.