Example.kt

// https://akarnokd.blogspot.ru/2017/09/rxjava-vs-kotlin-coroutines-quick-look.html
import kotlinx.coroutines.experimental.*

suspend fun f1(i: Int): Int {
    Thread.sleep(if (i != 2) 2000L else 200L)
    return 1
}

suspend fun f2(i: Int): Int {
    Thread.sleep(if (i != 2) 2000L else 200L)
    return 2
}

suspend fun coroutineWay() {
    val t0 = System.currentTimeMillis()
    repeat(3) { i ->
        println("Attempt ${i + 1} at T=${System.currentTimeMillis() - t0}")
        val v1 = async(CommonPool) { f1(i) }
        val v2 = async(CommonPool) { f2(i) }
        withTimeoutOrNull(500) {
            val r1 = v1.await()
            val r2 = v2.await()
            r1 + r2
        }?.let { sum ->
            println(sum)
            println("End at T=${System.currentTimeMillis() - t0}")
            return // success, may return computed sum
        }
        println("Timeout at T=${System.currentTimeMillis() - t0}")
    }
    error("Too many attempts, operation aborted")
}

fun main(args: Array<String>) = runBlocking {
    coroutineWay()
}