Use OffScreenCanvas and WebWorkers

[johannbuscail]

Issue

Slowness

Solution

Instead of using just the main thread with a canvas that needs to render,
It would be faster to use a WebWorker to create another thread and use an OffScreenCanvas to not render everything when it's not needed.

Related:

fabricjs/fabric.js#3941
fabricjs/fabric.js#5231

https://caniuse.com/?search=offscreencanvas
https://stackoverflow.com/questions/50799546/use-fabricjs-and-offscreencanvas-to-work-with-workers-html5
https://medium.com/samsung-internet-dev/offscreencanvas-workers-and-performance-3023ca15d7c7
https://bugs.chromium.org/p/chromium/issues/detail?id=923007

[nmitic]

Any news about supporting this one?