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Hello, World!  When using `suspendCancellableCoroutine` I sometimes see code that calls `cont.resume(result)` but when I try that, it's looking for a `onCancellation` argument, I so I need to do `cont.resume(result) {}` instead.   Ideas why?  (May be relevant: I'm in Kotlin-js).

The first `resume`  needs an import I think. (It's an extension function).

Thought of it but couldn't find the right one, and IJ didn't help.  But I finally found it:
```import kotlin.coroutines.resume```
:smile:   Thanks!

I thought that if you dont need the cancellation exception, you use `suspendCoroutine` instead of `suspendCancellableCoroutine`?

Yes. I assume that `cont.invokeOnCancellation`  is being used.

turns out I was using `suspendCancellableCoroutine` when I could use `suspendCoroutine` :slightly_smiling_face:  Thanks a lot

Well, `suspendCoroutine` is when you cannot and don't want to support cancellation at all, which can lead to memory leaks in some cases if your code never resumes or resumes after a long time while it should have been cancelled.

So, I tend to think the opposite scenario is more correct: one might use `suspendCoroutine` when `suspendCancellableCoroutine` could/should be used.

With supporting cancellation, do you mean passing something like `removeEventListener` to the onCancellation?

<@US36YQXN3> There's multiple ways of doing it. You mentioned one way to do it. Basically, you need to unregister or cancel the callback, and do it from `onCancellation` or in a `try`/`finally` or `try`/`catch(e: CancellationException)` block surrounding the `suspendCancellableCoroutine` call.

Here's a real world example that allows to wait for a click on a `View` in an Android app: <https://github.com/LouisCAD/Splitties/blob/49e2ee566730aaeb14b4fa9e395a677c3f214dba/modules/views-coroutines/src/androidMain/kotlin/splitties/views/coroutines/VisibilityAndClicks.kt#L34-L51>