Could this package be merged with atomic-primops?

[mitchellwrosen]

Hey! I just thought I'd float the idea of merging this package with atomic-primops, which also exposes a similar counter type.

It seems this package has a default cmm implementation, whereas atomic-primops does not. Perhaps that code could be contributed to atomic-primops as well?

Having two atomic counter packages is of course not the end of the world, but it would be (slightly) better for ecosystem discoverability and cohesion to have just one.