Whats the best way to efficiency suspend coroutine indefinitely? ```delay(Long.MAX_VALUE)``` or ```M...

# coroutines

[Vlad]

Whats the best way to efficiency suspend coroutine indefinitely?

delay(Long.MAX_VALUE)

or

Mutex(true).run { lock() }

or something else?

[diesieben07]

suspendCoroutineUninterceptedOrReturn { COROUTINE_SUSPENDED }

But if you plan to ever resume the coroutine, you need to use suspendCoroutineOrReturn instead, otherwise the interceptor (dispatcher) is lost.

[tseisel]

The mutex approach is quite expensive and its intent is unclear. delay(Long.Max_VALUE) is fine.
You can also try suspendCancellableCoroutine<Nothing> {}

[streetsofboston]

Using delay(Long.MAX_VALUE) may raise issues when unit-testing your Coroutines code. The max-value of the long may cause an overflow when calling advanceTimeBy on your test-coroutine-dispatcher, making the delay an 'negative' value. Using suspendCancellableCoroutine does not have that problem

[louiscad]

I have an awaitCancellation() function that returns Nothing and is using suspendCancellableCoroutine<Nothing> { }

[elizarov]

@louiscad I like the awaitCancellation name. Maybe worth adding to the library.

[louiscad]

I think I already had a discussion about that with you in the past @elizarov and you were like "let's see". I'll send a PR this weekend 👍

[elizarov]

I’ve been hearing this question a few times already, so it looks like it needs some “out of the box” solution.

[elizarov]

dealy(Long.MAX_VALUE) also works great, BTW, but it does not capture the intent as well as awaitCancellation

[Zach Klippenstein (he/him) [MOD]]

So if awaitCancellation was added as a general function, it wouldn’t need to be defined specially for channelFlow anymore, right?

[louiscad]

@Zach Klippenstein (he/him) [MOD] `channelFlow`/`callbackFlow` get the awaitClose (not awaitCancellation) function from ProducerScope. awaitCancellation would be able to replace the no argument version, and would be usable in conjunction with a `try`/`finally` pair, but it would not be the same as the awaitClose { ... } overload taking a lambda.

Do you think awaitCancellation should also have an overload accepting a lambda executed on cancellation?

[louiscad]

(I'm late for the PR, I still plan on doing it this week, next Friday is my next deadline.)