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kotlinlang

Whats the best way to efficiency suspend coroutine indefinitely?
```delay(Long.MAX_VALUE)```
or
```Mutex(true).run { lock() }```
or something else?

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

The mutex approach is quite expensive and its intent is unclear. `delay(Long.Max_VALUE)` is fine.
You can also try `suspendCancellableCoroutine&lt;Nothing&gt; {}`

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

I have an `awaitCancellation()` function that returns `Nothing` and is using `suspendCancellableCoroutine&lt;Nothing&gt; { }`

<@U3ZLHBTLG> I like the `awaitCancellation` name. Maybe worth adding to the library.

I think I already had a discussion about that with you in the past <@U2E974ELT> and you were like "let's see". I'll send a PR this weekend :thumbsup:

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

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

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

<@U0KMMQA20> `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?

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