constexpr explicit sentinel(cache_latest_view& parent);
constexpr sentinel_t<V> base() const;
friend constexpr bool operator==(const iterator& x, const sentinel& y);
friend constexpr range_difference_t<V> operator-(const iterator& x, const sentinel& y)
requires sized_sentinel_for<sentinel_t<V>, iterator_t<V>>;
friend constexpr range_difference_t<V> operator-(const sentinel& x, const iterator& y)
requires sized_sentinel_for<sentinel_t<V>, iterator_t<V>>;