Function yield_now

pub fn yield_now() -> impl Future<Output = ()>

Yield from the current task once, allowing other tasks to run.

This can be used to easily and quickly implement simple async primitives without using wakers. The following snippet will wait for a condition to hold, while still allowing other tasks to run concurrently (not monopolizing the executor thread).

while !some_condition() {
    yield_now().await;
}

The downside is this will spin in a busy loop, using 100% of the CPU, while using wakers correctly would allow the CPU to sleep while waiting.

The internal implementation is: on first poll the future wakes itself and returns Poll::Pending. On second poll, it returns Poll::Ready.