如何检测tvOS remote上按下的音量按钮

override func viewDidLoad() {
    super.viewDidLoad()
    // 设置远程控制事件的接收者
    UIApplication.shared.beginReceivingRemoteControlEvents()
    self.becomeFirstResponder()
}

override func remoteControlReceived(with event: UIEvent?) {
    if event?.type == .remoteControl {
        switch event!.subtype {
        case .remoteControlTogglePlayPause:
            // 处理播放/暂停按钮按下事件
            break
        case .remoteControlPreviousTrack:
            // 处理上一曲按钮按下事件
            break
        case .remoteControlNextTrack:
            // 处理下一曲按钮按下事件
            break
        case .remoteControlPlay:
            // 处理播放按钮按下事件
            break
        case .remoteControlPause:
            // 处理暂停按钮按下事件
            break
        case .remoteControlStop:
            // 处理停止按钮按下事件
            break
        case .remoteControlBeginSeekingBackward:
            // 处理开始向后快进按钮按下事件
            break
        case .remoteControlEndSeekingBackward:
            // 处理结束向后快进按钮按下事件
            break
        case .remoteControlBeginSeekingForward:
            // 处理开始向前快进按钮按下事件
            break
        case .remoteControlEndSeekingForward:
            // 处理结束向前快进按钮按下事件
            break
        default:
            break
        }
    }
}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    // 停止接收远程控制事件
    UIApplication.shared.endReceivingRemoteControlEvents()
    self.resignFirstResponder()
}