erate through all the elements again.
The iterators of the same iterable can be stepped through independently,
but should return the same elements in the same order,
as long as the underlying collection isn't changed.</p>
<p>Modifying the collection may cause new iterators to produce
different elements, and may change the order of existing elements.
A <a href="dart-core/List-class.html">List</a> specifies its iteration order precisely,
so modifying the list changes the iteration order predictably.
A hash-ba