在UIPageViewController中删除循环AVPlayer观察器

class MyPageViewController: UIPageViewController {
    var player: AVPlayer?
    var playerLayer: AVPlayerLayer?
    var playerItem: AVPlayerItem?
    var timeObserverToken: Any?
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 创建AVPlayer对象和AVPlayerLayer对象，并将其关联起来
        
        // 创建AVPlayerItem对象，并将其添加到AVPlayer中
        
        // 添加循环AVPlayer观察器
        timeObserverToken = player?.addPeriodicTimeObserver(forInterval: CMTime(value: 1, timescale: 60), queue: DispatchQueue.main) { [weak self] time in
            // 观察器回调方法
        }
    }
    
    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        
        // 删除循环AVPlayer观察器
        if let token = timeObserverToken {
            player?.removeTimeObserver(token)
            timeObserverToken = nil
        }
        
        // 停止播放视频
        player?.pause()
        
        // 释放资源
        player = nil
        playerLayer?.removeFromSuperlayer()
        playerLayer = nil
        playerItem = nil
    }
}