将 AVPlayerItem 转换为 NSData

有这样一种需求，从相册获取选取视频并取得视频的路径，以及将视频转换位NSData ，代码如下：

PHVideoRequestOptions *requestOptions = [[PHVideoRequestOptions alloc] init];
            requestOptions.version = PHImageRequestOptionsVersionCurrent;
            requestOptions.deliveryMode = PHVideoRequestOptionsDeliveryModeAutomatic;
            [[PHImageManager defaultManager] requestPlayerItemForVideo:model.asset options:requestOptions resultHandler:^(AVPlayerItem * _Nullable playerItem, NSDictionary * _Nullable info) {
                NSURL *fileURL = [(AVURLAsset *)playerItem.asset URL];
                NSData *videoData = [NSData dataWithContentsOfURL:fileURL];
                NSLog(@"tmpData Size: %lu",videoData.length);
            }];

另一种方法
AVURLAsset *urlAsset = (AVURLAsset *)asset;
     NSData *videoData = [NSData dataWithContentsOfURL:urlAsset.URL];
     if (videoData) {
         NSLog(@"videoData Size: %lu", videoData.length);
     }