 order),
or they may leave it unspecified (for example a hash-based <a href="dart-core/Set-class.html">Set</a>
may iterate in any order).</p>
<p>Each time <code>iterator</code> is read, it returns a new iterator,
which can be used to iterate 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