kotlin coroutines

import kotlinx.coroutines.experimental.future.await
import kotlinx.coroutines.experimental.future.future
import java.util.concurrent.CompletableFuture

fun main(args: Array<String>) {
    val f : CompletableFuture<String> = future {
        (1..5).map {
            startLongAsyncOperation(it).await()
        }.joinToString("\n")
    }

    println(f.get())
}

fun startLongAsyncOperation(num: Int): CompletableFuture<Int> = future {
    42
}