[Rusky]

A Rust async function doesn't work like Dart 1- it doesn't suspend immediately (i.e. return back to the event loop to be scheduled), it just doesn't run to the first await until it's actually awaited or otherwise `poll`ed itself.

So the performance concern simply does not apply- Rust suspends the same number of times as Dart 2. The race condition concern might, depending on how you look at it, but in return the execution model from within a Future is much more straightforward and predictable.