Support async calls in defer bodies

[tourultimate]

+1 on the proposal. Regarding cancellation, I think the default should be inheriting the cancellation state of the Task. To me, it would be unexpected to default it the other way around.

In other words, I’m 100% on board with this:

@ktoso

Step 1) I personally think “async defer” should be just that “a defer that can do async” and change absolutely nothing about cancellation behavior.