create

    fn create(ev: *Evented) error{OutOfMemory}!*Fiber {
        const thread: *Thread = .current();
        if (@atomicRmw(?*Fiber, &thread.free_queue, .Xchg, finished, .acquire)) |free_fiber| {
            assert(free_fiber != finished);
            @atomicStore(?*Fiber, &thread.free_queue, free_fiber.status.free_next, .release);
            return free_fiber;
        }
        const active_threads = @atomicLoad(u32, &ev.threads.active, .acquire);
        for (0..@min(max_steal_free_search, active_threads)) |_| {
            defer thread.steal_free_search_index += 1;
            if (thread.steal_free_search_index == active_threads) thread.steal_free_search_index = 0;
            const steal_free_search_thread =
                &ev.threads.allocated[0..active_threads][thread.steal_free_search_index];
            if (steal_free_search_thread == thread) continue;
            const free_fiber =
                @atomicLoad(?*Fiber, &steal_free_search_thread.free_queue, .monotonic) orelse continue;
            if (free_fiber == finished) continue;
            if (@cmpxchgWeak(
                ?*Fiber,
                &steal_free_search_thread.free_queue,
                free_fiber,
                null,
                .acquire,
                .monotonic,
            )) |_| continue;
            @atomicStore(?*Fiber, &thread.free_queue, free_fiber.status.free_next, .release);
            return free_fiber;
        }
        @atomicStore(?*Fiber, &thread.free_queue, null, .monotonic);
        return @ptrCast(try ev.allocator().alignedAlloc(u8, .of(Fiber), allocation_size));
    }