I’d recommend reading
https://github.com/JetBrains/kotlin-native/blob/master/CONCURRENCY.md as it covers important aspects of vision on concurrency in Kotlin/Native. We do not support shared heap, as believe that it is not really reliable programming model. Also this memory management model allows pauseless execution + cycle collector, unavailable on other platforms. However, in interop scenarios, where there are existing APIs with different view on how concurrency to be done, we will implement some helper functionality, allowing easier debugging and implementing callbacks, executed on other threads. See this example
https://github.com/JetBrains/kotlin-native/tree/master/samples/globalState for various solution of the global state problem.