A yield_now/yield_local alternative that allows the thread to go to sleep about rayon HOT 3 OPEN

pub struct Parker;
pub struct Unparker;

impl Parker {
    /// Either does one job, or does an additional round of polling via Sleep, eventually putting the thread to sleep, blocking the
    /// thread until woken up by rayon or the provided Waker.
    pub fn yield_or_sleep(&self) -> Yield {}
}

// The converted Wakes up the paired thread.
impl From<Unparker> for std::task::Waker {
    ...
}

/// Linked to WorkerThread::current
pub fn pair() -> (Parker, Unparker) {}