Error on setMediaDuration when mediasource readyState != 'open'
Created by: jimmymic
Fix for bug where StreamController.reset() is called but event handler is called after the reset and mediasource.readystate is no longer open.
Playback fails with: Uncaught DOMException: Failed to set the 'duration' property on 'MediaSource': The MediaSource's readyState is not 'open'