title: AVPlayer skip by a specific time
body: <p>I'm looking for solution to make a function, which forwards video in AVPlayer by for example 10 % of the video each time the user clicks on the button (10% + another 10 % next click + another 10 % next click etc) from the current state in video. So far, I've found a <code>seek(to:CMTimeMakeWithSeconds(seconds: Float64, preferredTimescale: Int32)</code> , however it moves the video TO a specific time every time, not BY a specific time. </p>
  
  <p>Any suggestions, please?</p>