luv does a fantastic job of sticking with Lua coroutines. The master branch still has zeromq in it, but the latest work is done in the ray branch. Sadly, it doesn't seem the project is moving, so most of the libuv features are not yet implemented the "ray" way.
Edit: Seems ray does have most of libuv features, sorry.
Edit: Seems ray does have most of libuv features, sorry.