Currently is only possible to detect keys pressed, but not the release event.

Had a look at the linux implementations and should be simple (didn't check mac/win/wasm), but I don't think that there's a way to make this backwards compatible other than creating another register/unregister methods.

Would you consider something like this? what would be a good api? new methods? an argument in the callback with some enum with KeyDown/KeyUp? another optional callback for the release?