Would be nice if you could find it again, because from what I know of tokio I'd assume you made other unrelated changes which fixed the issue: tokio only has on

Would be nice if you could find it again, because from what I know of tokio I'd assume you made other unrelated changes which fixed the issue: tokio only has one runtime type, the flavour's effects are internal, the top-level future (run by Runtime::block_on) is always !Send, but from that you can only run Send futures (via spawn and spawn_blocking), unless you create a LocalSet. current_thread doesn't even create an implicit LocalSet, if you try to `spawn_local` from the top-level of a current_thread runtime you get a panic, exactly like a multi_thread runtime.