template <typename Ty1, typename Ty2>
    struct duplex
    {
        Ty1 first;
        Ty2 second;

        bool operator==(const duplex<Ty1, Ty2>& dup) const
        {
            return (first == dup.first
                && second == dup.second);
        }
    };

    template <typename Ty1, typename Ty2>
    struct std::hash<lwlog::details::duplex<Ty1, Ty2>>
    {
        std::size_t operator()(const lwlog::details::duplex<Ty1, Ty2>& dup) const
        {
            return std::hash<Ty1>{}(dup.first) ^ std::hash<Ty2>{}(dup.second);
        }
    };