Method delayedTask

async_simple/uthread/test/UthreadTest.cpp:42–50

    template <class Func>
    void delayedTask(Func&& func, std::size_t ms) {
        std::thread(
            [f = std::move(func), ms](Executor* ex) {
                std::this_thread::sleep_for(std::chrono::milliseconds(ms));
                ex->schedule(std::move(f));
            },
            &_executor)
            .detach();
    }

    template <class T>
    struct Awaiter {