int id = 0;

std::string payload;

WorkItem() {

// 确保多线程下id唯一

static std::atomic<int> counter{0};

id = ++counter;

std::cout << "WorkItem #" << id << " created\n";

}

~WorkItem() {

std::cout << "WorkItem #" << id << " destroyed\n";

}

// 配置池

using Pool = ThreadSafeObjectPool<WorkItem>;

Pool::Config cfg;

cfg.max_cached = 3;

cfg.resetter = reset_work_item;

Pool pool(cfg);

// 启动4个线程，每个获取5个对象

const int num_threads = 4;

const int items_per_thread = 5;

std::vector<std::thread> threads;

for (int tid = 0; tid < num_threads; ++tid) {

// emplace_back( lambda ), 启动一个线程，运行这个lambda函数，并把改线程对象加入到threads数组中

threads.emplace_back([&, tid]() {

std::vector<std::unique_ptr<WorkItem>> local_items;

for (int i = 0; i < items_per_thread; ++i) {

auto item = pool.acquire();

if (item) {

item->payload = "Thread" + std::to_string(tid) + "-Job" + std::to_string(i);

// 模拟工作

std::this_thread::sleep_for(std::chrono::milliseconds(10));

local_items.push_back(std::move(item)); // 暂存，稍后归还

}

}

// 归还所有对象

for (auto& item : local_items) {

pool.release(std::move(item));

}

});

}

// 等待所有线程结束

for (auto& t : threads) {

t.join();

}

std::cout << "\nFinal cached objects in pool: " << pool.cached_size() << "\n";

return 0;

}