Struct SlotNotify 

pub struct SlotNotify {
    inner: Arc<Mutex<SlotNotifyInner>>,
}

Runtime-agnostic multi-waker notification primitive.

Uses a generation counter to detect notification events: notify_waiters bumps the generation, and notified futures compare the generation at creation time against the current one on each poll(). This prevents two race conditions a simple waker-vector approach cannot handle:

1. Latent wake. A notified future registers its waker on first poll(). If notify_waiters fires between the creation of the future and that first poll, the waker-vector is empty and the notification is lost. With a generation counter, gen_at_creation already captures the pre-notification value, so the first poll() sees the advanced generation and returns Ready.

2. Spurious Ready. A second poll() of an already-registered future can return Ready unconditionally if the notification check is only done on registration. Generation re-check on every poll() prevents this.

Uses unique IDs per waiter so that dropping a future cleanly removes its waker from the vector — no waker leak on cancellation. No tokio dependency — works with any async runtime.

Clone is cheap (clones the inner Arc).

Fields

inner: Arc<Mutex<SlotNotifyInner>>

Implementations

impl SlotNotify

pub fn new() -> Self

pub fn notify_waiters(&self)

Wake all parked waiters.

Bumps the generation counter before draining wakers so that futures created between this call and their first poll() see the advanced generation and return Ready immediately.

The guard is released before any waker runs. Waker::wake executes arbitrary executor code, and an executor that polls the woken task inline re-enters SlotNotifyFuture::poll — or its Drop — both of which lock this same non-reentrant mutex. Waking under the guard is therefore a self-deadlock against exactly the runtimes this type advertises support for; tokio only enqueues, so the shipped path never hit it. Draining into a local buffer costs one allocation per notification that actually has waiters to wake, and nothing at all when it does not.

pub fn notified(&self) -> SlotNotifyFuture

Return a future that completes the next time notify_waiters is called.

The future captures the current generation at creation time. A concurrent notify_waiters call that fires before the first poll() will have bumped the generation, so the future still completes — no notification is lost.

Trait Implementations

impl Clone for SlotNotify

fn clone(&self) -> SlotNotify

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.