https://developer.wordpress.org/reference/files/wp-includes/requests/utility/filterediterator.php/
wp-includes/Requests/Utility/FilteredIterator.php | Developer.WordPress.org
File: wp-includes/Requests/Utility/FilteredIterator.php
php developerwpincludesrequestsutility
https://www.d.umn.edu/~gshute/cs4521/docs/gshute/util/FilteredIterator.html
: Class FilteredIterator
class