Because of the Ktor websocket client is not available for Kotlin native yet, I've started working on wrapping OkHttp for JVM/Android and SocketRocket for iOS and providing a common API.
And what should I say? It took me a while to get everything set up and even longer to get cinterop working for including SocketRocket. But it's working now, I'm incredibly amazed. This is the first time working with a multiplatform setup that actually makes sense! This stuff is super exciting!