 private let PlayerTracksKey = "tracks"
 private let PlayerPlayableKey = "playable"
 private let PlayerDurationKey = "duration"
-private let PlayerRateKey = "rate"
 private let PlayerTimeControlStatusKey = "timeControlStatus"
 
 // KVO player item keys

            strongSelf.playbackDelegate?.playerCurrentTimeDidChange(strongSelf)
        })
        
        self._avplayer.addObserver(self, forKeyPath: PlayerRateKey, options: [.new, .old], context: &PlayerObserverContext)
        if #available(iOS 10.0, tvOS 10.0, *) {
            self._avplayer.addObserver(self, forKeyPath: PlayerTimeControlStatusKey, options: [.new, .old], context: &PlayerObserverContext)
        }

            }

        } else if context == &PlayerObserverContext {
            
            // PlayerTimeControlStatusKey
            
