I chose rx.annotations but am open to suggestions for a better package name. It could perhaps be rx.lifecycle. I don't want rx.util or rx.common. We worked hard to eliminate those catch-all packages.

+1 on annotations

Thanks for voting on this so it's not just me!

rx.annotations is okay with me as well.

I'm merging this then so we can start using it on some of the other PRs.

Thanks @daschl and @akarnokd for the review.