I wrote a quick overview of what I learned getting Go working with Kotlin utilising callbacks and coroutines:
https://clinetworking.wordpress.com/2018/04/30/building-a-kotlin-android-app-with-go-logic/
I also created an example app which is linked in the blog post for those who want to get started quickly.
Happy to hear any feed back. My main goal is to help someone else get started easier.