currentMediaItem is empty when a CastPlayer is being used #25

I'm using a MediaLibraryService that switches the player from ExoPlayer to CastPlayer when a CastSession is available. When the ExoPlayer is active, calling getCurrentMediaItem() from a MediaController returns the correct MediaItem, but if the same call is done when the CastPlayer is the active one, I receive an empty MediaItem.

The method getWindow(...) inside CastTimeline is the one creating and using an empty MediaItem instead of the expected currentMediaItem.