         #keyPath(currentItem),
         #keyPath(currentItem.playbackLikelyToKeepUp),
         #keyPath(currentItem.playbackBufferEmpty),
-        #keyPath(currentItem.duration)
-        //        #keyPath(currentItem.tracks)
+        #keyPath(currentItem.duration),
+        #keyPath(currentItem.tracks)
     ]
     
     private var observerContext = 0

            self.postStateChange(newState: newState, oldState: self.currentState)
            self.currentState = newState
        }

        if let currentEvent: PKEvent = event {
           self.postEvent(event: currentEvent)
        }

    
    // Attempt load and test these asset keys before playing.
    let assetKeysRequiredToPlay = [
        "playable",
        "tracks"
    ]
    
    private var avPlayerLayer: AVPlayerLayer!
