title: RPScreenRecorder startCapture is not recording in background
body: <p>I am trying ScreenRecording implementation using Replaykit. It is currently able to record app screen, but when I am putting it in background for device screen recording, then <code>RPScreenRecorder.startCapture</code> callback is not getting called.</p>
  
  <pre><code>let recorder = RPScreenRecorder.shared()
  
  recorder.delegate = self
  recorder.startCapture(handler: { (buffer, bufferType, err) in
        self.counter = self.counter.advanced(by: 1)
        print(self.counter)
  //    self.assetWriter.write(buffer: buffer, bufferType: bufferType)
     }, completionHandler: {
     if let error = $0 {
        print(error)
     }
   })
  
  // stop recording
  
  recorder.stopCapture {
     if let err = $0 {
         print(err)
     }
  // self.assetWriter.finishWriting()
  }
  </code></pre>
  
  <p>Do we need to allow any permissions for background access.</p>