public IObservable<IBitmap> GetImage(Uri uri, TimeSpan offset) => _cache.LoadImageFromUrl(uri.ToString(), false, null, null, offset.GetAbsoluteUtc());
public IObservable<IBitmap> GetImage(Uri uri, TimeSpan offset, DesiredImageSize desiredDimensions) { var url = uri.ToString(); return _cache.LoadImageFromUrl(GetDimensionKey(uri, desiredDimensions), url, false, desiredDimensions.Width, desiredDimensions.Height, offset.GetAbsoluteUtc()); }