`SvgImageSource.ReadFromStreamAsync` could be optimized

[Youssef1313]

What would you like to be added

Looking at the code:

#if __ANDROID__ || __SKIA__
    private async Task<ImageData> ReadFromStreamAsync(Stream stream, CancellationToken ct)
    {
        if (stream.CanSeek && stream.Position != 0)
        {
            stream.Position = 0;
        }

        var memoryStream = new MemoryStream();
        await stream.CopyToAsync(memoryStream, 81920, ct);
        var data = memoryStream.ToArray();
        return ImageData.FromBytes(data);
    }
#endif

Two optimizations come to mind:

• Check if the given stream is already MemoryStream, and if so, skip creating a new MemoryStream and copying to it.
• Avoid the array allocation done by memoryStream.ToArray(). There are two ways that come in mind:
  • Instead of giving byte[] to ImageData, give it the MemoryStream. Note that:
    • the array is actually used to create a MemoryStream back again here
    • Not sure if this optimization will not be safe if the given stream was already MemoryStream and we are reusing the same instance.
  • Use TryGetBuffer, which will reuse the internal array instead of creating a new array. I think this option makes more sense.

Why is this needed

No response

For which platform

No response

Anything else we need to know?

No response

[Youssef1313]

Trying to implement this fix, I found out that I need to change the signature of TryLoadSvgDataAsync which is public. So probably this would be postponed to Uno 6, unless someone sees a clever way of doing it without breaking the public API.

[Youssef1313]

There is no enough evidence that it's really an issue in practice. Closing out