Comment by Darmani
2 days ago
Just investigated -- looks like this works now! Yay!
For this family of examples, had been completely stymied by AsyncFnOnce not being released yet. IIRC it had been in the works for several years, was still an experimental feature when I was trying to use it, and I gave up after much frustration at trying to get a version of Rust with experimental features working under devenv (nix).
A subtraction then to my frustrations with Rust -- though I'd still be very wary of doing this, having seen how fragile higher-order functions have been in the past.
That explains it. I think async closures were stabilized a year ago. Before that, you'd have needed to write out the async signature as non-async with futures (that's what async is syntactic sugar for, anyway). Something like: