title: Shift AVPlayer captions when subview overlaps them
body: <p>Is it possible to shift the system captions that display for a video should a subview (non-native, custom player controls) appear over them? The captions displayed are text WebVTT captions.</p>
  
  <p>On certain screen sizes, when I shift to landscape, our custom seek bar controls overlap captions that appear at the bottom of the player.</p>