threading experiment

thign.hpp

#include <mutex>
template<typename T,typename M=std::mutex>
struct protected_variable
{
    T data;
    M data_mutex;
    
    template <typename F> 
    void with(F f){
        std::lock_guard<M> lock(data_mutex);
        f(data);
    }
  std::pair<std::lock_guard<M>,T&> get(){
    return std::make_pair(std::lock_guard<M>(data_mutex),data);
  }
};