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Hi i have two long operation.. and i’d like launch in parallel…
`customScope.launch{`
    `action1()`
    `action2()`

i’d like launch in parallel and  when 2 methods end your action i have to invoke a method

Hey there! You would probably want to use `async()` instead of `launch()` in this case, so that can you can call `await()` and wait for the result(s). Check out: <https://kotlinlang.org/docs/composing-suspending-functions.html#concurrent-using-async>

Ok ..
`*val* one = async { doSomethingUsefulOne() }`
    `*val* two = async { doSomethingUsefulTwo() }`
 i don’t understand how invoke a method when both async has finished your actions

Ah. If you call `await()` on both of them, whichever finished first will return immediately, whereas the one that is taking longer will block until it's done.

So let's say one takes 10 seconds and two takes 5, if you call `await()` on both then it will block for 10 seconds, but as two already finished in the meantime, your execution time will be 10 seconds in total (roughly of course)

```customScope.launch {
  coroutineScope {
    launch { action1() }
    launch { action2() }
  }
  println("action1 and action2 finished")
  doSthNow()
}```

This will launch a new coroutine which then launches action1 and 2 in parallel. Once the coroutineScope block exists, both actions completed

but  are action1() and action1() launched in parallel?