Support multithreaded coroutines for Kotlin/Native in coroutines-interop

[arkivanov]

Currently corotuines-interop is implemented differently for Kotlin/Native, using runBlocking. This is because Job can not be frozen. It has one significant limitation - you can't use coroutines-interop on main thread and subscribeOn is required. Looks like after Kotlin/kotlinx.coroutines#1648 it will be fixed and we will be able to use same implementation as for JVM.

[arkivanov]

#314 seems working with mt coroutines version. We could make a separate branch for mt coroutines interop as well, and publish. Perhaps publication of only coroutines-interop module would be enough.

It will lift the runBlocking limitation in native. The interop will be truly async, there will be no requirement to subscribe only on a background scheduler.

Is there a demand?

@CherryPerry JFYI

[nectar1]

Cool news. Lets do separate branch

[arkivanov]

Multi-threaded coroutines interop is published with -nmtc version suffix. Please see the corresponding Readme section for more information.