        typename T::context& get_context(const request& req)
        {
            static_assert(black_magic::contains<T, Middlewares...>::value, "App doesn't have the specified middleware type.");
            auto& ctx = *reinterpret_cast<context_t*>(req.middleware_context);
            return ctx.template get<T>();
        }
        typename T::context& get_context(const request& req)
        {
            static_assert(black_magic::contains<T, Middlewares...>::value, "App doesn't have the specified middleware type.");
            auto& ctx = *reinterpret_cast<context_t*>(req.middleware_context);
            return ctx.template get<T>();
        }