This dispatcher guarantees that, at all times, the coroutine is executed in a specific thread. To create a dispatcher of this type you have to use newSingleThreadContext():

fun main(args: Array<String>) = runBlocking {
    val dispatcher = newSingleThreadContext("myThread")

    launch(dispatcher) {
        println("Starting in ${Thread.currentThread().name}")
        delay(500)
        println("Resuming in ${Thread.currentThread().name}")
    }.join()
}

This will always execute in that same thread, even after any suspensions: