friend constexpr auto operator<=>( const /*iterator*/& x, const /*iterator*/& y )
Compares the underlying iterators.
current_ be the underlying tuple-like object of iterators to elements of adapted views.
These functions are not visible to ordinary unqualified or qualified lookup, and can only be found by argument-dependent lookup when
std::ranges::zip_view::iterator<Const> is an associated class of the arguments.
!= operators are synthesized from operator<=> and operator== respectively.
|x, y||-||iterators to compare|
 Return value
The result of comparison
 See also
| compares a sentinel with an iterator returned from zip_view::begin |