title: Add Storyboards/Trickplay using either WebVTTT or JSON using Exo player
body: <p>I am trying to implement Video thumbnail while seeking the seek bar using MUX(<a href="https://docs.mux.com/docs/storyboard-guide" rel="nofollow noreferrer">https://docs.mux.com/docs/storyboard-guide</a>) in exo-player but unable to find the sample for it so did any one implement it or is there any other way to achieve it?</p>