Method Write

13-Multithreading/code/shared_mutex.cpp:18–22

    }
    
    void Write(int d) {
        std::lock_guard exclusiveLock{ mutex_ };
        std::this_thread::sleep_for(300ms); // Assuming we need 300ms to write.
        data_ = d; 
    }
private:
    std::shared_mutex mutex_;
    int data_ = 0;