isfy the
predicate <code>test</code>.</p>
<p>The matching elements have the same order in the returned iterable
as they have in <a href="dart-core/Iterable/iterator.html">iterator</a>.</p>
<p>This method returns a view of the mapped elements.
As long as the returned <a href="dart-core/Iterable-class.html">Iterable</a> is not iterated over,
the supplied function <code>test</code> will not be invoked.
Iterating will not cache results, and thus iterating multiple times over
the returned <a href="dart-core/Iter