Async: Awaiting a future doesn't continuously poll, hangs program

[SkiFire13]

@quinedot

The Waker is a vtable basically, a handful of pointers, so probably it doesn't really matter. But yeah wake_by_ref makes more sense, given that you're not storing it.

It does kinda matter because cloning a Waker involves calling one of those function pointers, thus dynamic dispatch. This is needed because it contains a data pointer whose ownership needs to be managed somehow, and that's done in that function call, usually with reference counting.