unsafe fn wake_by_ref<W: Wake + Send + Sync + 'static>(waker: *const ()) {
        let waker = unsafe { ManuallyDrop::new(Arc::from_raw(waker as *const W)) };
        <W as Wake>::wake_by_ref(&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 heap as the
source `Arc`, while increasing a reference count. When the last `Arc`
pointer to a given allocation is destroyed, the value stored in that allocation (often
referred to as "inner value") is also dropped.

Shared references in Ru
benchmarks/haystacks/code/rust-library.rs