All you have to do is register a hook.

continuation.invokeOnCancellation

or something like that.

Say you’re working with Google play api, and you want to use the

addOnCompleteListener

callback with coroutines, so you decide to wrap this in a

suspendCancellableCoroutine

to get the power of coroutines with your callback. If the coroutine gets cancelled, the code in the

addOnCompleteListener

could still be running. Which means once your addOnCompleteListener callback finishes, before calling

resume

on the suspended function, its probably a good idea to check if that coroutine has been cancelled

return suspendCancellableCoroutine { cont ->
        addOnCompleteListener {
            val e = exception
            if (e == null) {
                @Suppress("UNCHECKED_CAST")
                if (isCanceled) cont.cancel() else cont.resume(result as T)
            } else {
                cont.resumeWithException(e)
            }
        }
    }

Example source https://github.com/Kotlin/kotlinx.coroutines/blob/master/integration/kotlinx-coroutines-play-services/src/Tasks.kt