title: AVCaptureSession Crashing when using webRTC
body: <p>I am using <code>WebRTC</code> and its using <code>AVCaptureSession</code>. It works fine a few times but sometimes its getting crashed with this Exception.</p>
  
  <blockquote>
    <p>Assertion failed: (_internal->figCaptureSession == NULL), function
    -[AVCaptureVideoPreviewLayer attachToFigCaptureSession:], file /BuildRoot/Library/Caches/com.apple.xbs/Sources/EmbeddedAVFoundation/EmbeddedAVFoundation-1187.37.2.1/Aspen/AVCaptureVideoPreviewLayer.m</p>
  </blockquote>