一 静音功能

通过调用系统的AVPlayer.muted来实现的

- (void)setMuted:(BOOL)muted {
    _muted = muted;
    self.player.muted = muted;
    if (self.audioMuteChange) {
        self.audioMuteChange(self, muted);
    }
    ...
}

播放进度条

/// 滑杆
@property (nonatomic, strong, readonly) ZFSliderView *slider;

使用ControlView自带的进度视图展示