pub(super) fn enqueue(&self, task: *const Task<Fut>) {
        unsafe {
            debug_assert!((*task).queued.load(Relaxed));

            // This action does not require any coordination
            (*task).next_ready_to_run.store(ptr::null_mut(), Relaxed);

            // Note that these atomic orderings come from 1024cores
            let task = task as *mut _;
            let prev = self.head.swap(task, AcqRel);
            (*prev).next_ready_to_run.store(task, Release);
        }
    }
The enqueue function from the 1024cores intrusive MPSC queue algorithm.
futures-util/src/stream/futures_unordered/ready_to_run_queue.rs