I've just published a new version of my kotlinx-io fork:
https://bintray.com/mipt-npm/dev/kotlinx-io/0.2.0-npm-dev-10. We use it internally in our projects and you are free to use it to test capabilities. This release is done for compatibility with new Kotlin-JS IR (it uses BOTH-mode).
WARNING! This is not the official JB release or JB repository. This is a fork with little added Binary functionality.