CoroutinesParallel.kt

//run array of (suspend () -> Unit) in parallel 
suspend fun parallel(vararg blocks: suspend () -> Unit) = runBlocking {
    for (block in blocks) {
        withContext(Dispatchers.Default) { block() }
    }
}

//run 2 functinos in pararllel then marge the result into pair
suspend fun <T1, T2> parallel2(block1: suspend () -> T1, block2: suspend () -> T2): Pair<T1, T2> =
    runBlocking {
        Pair(
            withContext(Dispatchers.Default) { block1() },
            withContext(Dispatchers.Default) { block2() }
        )
    }

//wrapper around Iterable<T>.flatMap to parrallel flatMap
suspend inline fun <T, R> Iterable<T>.flatMapParallel(
    crossinline transform: suspend (T) -> Iterable<R>
): List<R> = runBlocking {
    flatMap { withContext(Dispatchers.Default) { transform(it) } }
}

//wrapper around Iterable<T>.map to parrallel map
suspend inline fun <T, R> Iterable<T>.mapParallel(
    crossinline transform: suspend (T) -> R
): List<R> = runBlocking {
    map { withContext(Dispatchers.Default) { transform(it) } }
}