Bucket

    const Bucket = struct {
        /// Used as a fast check for `wake` to avoid having to acquire `mutex` to discover there are no
        /// waiters. It is important for `wait` to increment this *before* checking the futex value to
        /// avoid a race.
        num_waiters: std.atomic.Value(u32),
        /// Protects `waiters`.
        mutex: ParkingMutex,
        waiters: std.DoublyLinkedList,

        /// Prevent false sharing between buckets.
        _: void align(std.atomic.cache_line) = {},

        const init: Bucket = .{ .num_waiters = .init(0), .mutex = .init, .waiters = .{} };
    }