Function apply_

develop/matchit/patterns.h:183–186

        template <class F, class Tuple>
        constexpr decltype(auto) apply_(F &&f, Tuple &&t)
        {
            return std::apply(std::forward<F>(f), drop<0>(std::forward<Tuple>(t)));
        }

        // as constexpr
        template <class F, class... Args>