I said in past:

Even if the library's API did not have the CS API, I believe CS would always be considered a public dependency of the library, since updating the CS version or removing CS impls or dependency on CS could break downstream builds.

So, if both portable-atomic 0.3 and portable-atomic 1 support CS (critical-section), updating from portable-atomic 0.3 to portable-atomic 1 may need to be considered a breaking change because it changes the version of the portable-atomic that needs to enable the CS feature in downstream.

This can be addressed by releasing the first portable-atomic with CS support as portable-atomic 1 and never releasing major version 2¹. The portable-atomic's API is stable enough that no changes should be necessary except for the removal of the outline-atomics feature that is no longer used.

TODO

• merge Add Cargo feature to use critical-section. #51; done
• remove the outline-atomics feature that is no longer used; done in fb5bc25
• (adjust docs) aed4e17...a6b3b95

Is there anything else you think is needed for this release?

ETA: I think I can finish this during this weekend.