With 1.0 release, is there any plans on native mt support in coroutines?

There are plans, there's an issue about that on GitHub, and they are still working on it, besides other things.

Yes, long-running issue...

Yes, we are working on it. Currently the problem is Native memory model, which is actively reworked.

Lol =)

We don’t know what is “reworked”, it is not necessary mean that it will have mutable state or expose threads. But there are obvious problems to have the same/similar API of MT coroutines which implemented with power of JMM and GC to handle shared mutable state