LaunchWithDispatcher.kt

sealed class Dispatcher {
    object Main : Dispatcher()
    object Background : Dispatcher()
}

fun launch(dispatcher: Dispatcher, block: suspend () -> Unit) {

    //Define a callback
    val callback = object : Continuation<Unit> {
        override val context = EmptyCoroutineContext
        override fun resumeWith(result: Result<Unit>) {}
    }

    //Create coroutine
    val continuation = block.createCoroutineUnintercepted(callback)

    //Start coroutine on specified dispatcher
    when (dispatcher) {
        Dispatcher.Main -> Handler(Looper.getMainLooper()).post {
            continuation.resumeWith(Result.success(Unit))
        }

        Dispatcher.Background -> thread {
            continuation.resumeWith(Result.success(Unit))
        }
    }
}