iterator property

@override Iterator<T> iterator

1. If the set's config has ConfigSet.sort true, it will iterate in the natural order of items. In other words, if the items are Comparable, they will be sorted by a.compareTo(b).
2. If the set's config has ConfigSet.sort false (the default), or if the items are not Comparable, the iterator order is the insertion order.

Implementation

@override
Iterator<T> get iterator => _s.iterator;