friend constexpr decltype(auto)
iter_move(const counted_iterator& i)
noexcept(noexcept(ranges::iter_move(i.current)))
requires input_iterator<I>;
template<indirectly_swappable<I> I2>
friend constexpr void
iter_swap(const counted_iterator& x, const counted_iterator<I2>& y)
noexcept(noexcept(ranges::iter_swap(x.current, y.current)));