Async: co-op: let other asyncs run

async fn foo() {
  while true {
    do_expehsive_computation();
   yield();
  }
}

Is there an idiomatic way in async rust to say "yield"; i.e. "let other scheduled async tasks run; then come back to me" ?

If you use Tokio, there's literally task::yield_now. For other executors, you may want to take inspiration from there (or look for something similar).

an alternative is futures_lite::yield_now()

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My fault for not stating this upfront. I am using wasm_bindgen_futures: wasm_bindgen_futures - Rust
which seems to shows nothing.

You can definitely use futures_lite::yield_now() as mentioned by @nerditation

The idea is just to await a Future that returns Poll::Pending once in order to yield back to the task scheduler. (This future, when polled, must also wake its own task immediately when returning Poll::Pending, in order to let the runtime know that the future may be polled again immediately.) There is nothing really "runtime-dependant" here.

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Note that if do_expensive_computation() takes lot of time you might want to insert some yield in there too. Also note that yield_now() and similar return a Future, so you need to .await them (as opposed to your example in the OP)

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