title: Do I have to dispose of ChangeNotifiers that have no listeners?
body: <p>If I can ensure that a ChangeNotifier either <strong>never had listeners</strong> or <strong>every added listener was removed</strong> at some point, do I still have to call <code>dispose</code> or is it safe to ignore it and move on? Because there are <strong>many</strong> ChangeNotifiers being created and removed every now and then, and disposing of all of them, even those that were never used would take some time.</p>