unsafe fn wake<W: Wake + Send + Sync + 'static>(waker: *const ()) {
        let waker = unsafe { Arc::from_raw(waker as *const W) };
        <W as Wake>::wake(waker);
    }
A thread-safe reference-counting pointer. 'Arc' stands for 'Atomically
Reference Counted'.

The type `Arc<T>` provides shared ownership of a value of type `T`,
allocated in the heap. Invoking [`clone`][clone] on `Arc` produces
a new `Arc` instance, which points to the same allocation on the hea
benchmarks/haystacks/code/rust-library.rs