struct Convert
{
    operator std::chrono::milliseconds()
    {
        std::cout << "operator std::chrono::milliseconds" << std::endl;
        return std::chrono::milliseconds(10);
    }

    operator int64_t ()
    {
        std::cout << "operator int64_t" << std::endl;
        return 5;
    }
};

Convert convert;

std::chrono::milliseconds m(convert);
std::cout << m.count() << std::endl;
int64_t i(convert);
std::cout << i << std::endl;