상속: VideoStreamViewModel
        public CsVideoStreamPlayerThumbnailViewModel(CsVideoStreamViewModel owner)
            : base(owner)
        {

        }
 private CsVideoStreamViewModel CreateVideoStreamViewModel(VideoStream videoStream)
 {
     var vm = new CsVideoStreamViewModel(this, videoStream);
     AvaliableVideoStreamsVM.Add(vm);
     return vm;
 }