How does this compare to something like the the Media Capture API? Looks like this uses `canvas.toDataURL()` which can be slow to serialize compared to `toBlob` or `canvas.captureStream(0).getVideoTracks()`
I've been using CropTarget.fromElement with a CaptureController: https://gist.github.com/akre54/e93ab2ce27999aecb109e38085f2e...