如何在成员变量中实例化由 std::async 创建的 future？

Question

当我尝试下面将 std::async 返回的 future 添加到成员变量中时，我做错了什么？

class PrinterDriver
{
    std::vector<std::future<void>> m_PendingFutures;

    public:

    int DriverThread() 
    {
        // Do something
    }
    
    void Start() 
    {
        m_PendingFutures.emplace_back(
           std::async(std::launch::async, 
               &PrinterDriver::DriverThread, this));
    }
}

我不明白这个错误，也不知道如何修复它：

error C2664: 'std::future::future(std::future &&) noexcept': 无法转换参数 1 从 '_Ty' 到 'std::future &&'

下面给出了作为我想使用它的上下文的完整代码：

#include <chrono>
#include <condition_variable>
#include <cstdio>
#include <future>
#include <thread>

class PrinterDriver
{
    std::mutex m_stop_driver_mutex;
    std::condition_variable_any m_StopDriverEvent;
    std::vector<std::future<void>> m_PendingFutures;

public:
    ~PrinterDriver() = default;

    int DriverThread()
    {
        printf("Printer driver started\n");
        auto quit = false;
        while (!quit)
        {
            // Wait 200 ms except if we are signaled to stop
            {
                using namespace std::chrono_literals;
                std::unique_lock<std::mutex> lock(m_stop_driver_mutex);
                const auto cv_status = m_StopDriverEvent.wait_for(lock, 200ms);
                quit = (cv_status == std::cv_status::no_timeout);
            }
        }
        printf("Printer driver stopped\n");
        return 0;
    }

    void Start()
    {
        // How to instantiate a future created by std::async in a member variable ?
        // Error C2664: 'std::future<void>::future(std::future<void> &&) noexcept':
        // cannot convert argument 1 from '_Ty' to 'std::future<void> &&'
        m_PendingFutures.emplace_back(std::async(std::launch::async, &PrinterDriver::DriverThread, this));
    }

    void Stop()
    {
        std::unique_lock<std::mutex> lock(m_stop_driver_mutex);
        m_StopDriverEvent.notify_all();
        for (auto&& future_handle : m_PendingFutures)
        {
            future_handle.get();
        }
        m_PendingFutures.clear();
    }
};

int main()
{
    PrinterDriver driver;
    driver.Start();
    std::this_thread::sleep_for(std::chrono::seconds(2));
    driver.Stop();
    return 0;
}