thread_pool_fix2.zig

    fn runWorker(self: *ThreadPool) void {
        const old_pool = tls_current_pool;
        tls_current_pool = self;
        defer tls_current_pool = old_pool;

        while (true) {
            const held = self.mutex.acquire();
            if (self.is_shutdown) {
                held.release();
                break;
            }

            if (self.run_queue.pop()) |runnable| {
                held.release();
                (runnable.callback)(runnable);
                continue;
            }

            var idle_node = IdleQueue.Node{ .data = .{} };
            self.idle_queue.prepend(&idle_node);
            held.release();
            idle_node.data.wait();
        }
    }