Addition of Metal 4?

This could be a major work... and I honestly don't fully grasp the scope of changes this may bring... but given major number bump, I thought it's a good timing to bring this up!

- https://metalbyexample.com/metal-4/
- https://developer.apple.com/documentation/Metal/understanding-the-metal-4-core-api


probably may add metal 4 only apis and stuff so wondering, what's the best way to go...