title: Equivalent of ChangeNotifierProvider widget in Riverpod
body: <p>Is there a widget equivalent of the ChangeNotifierProvider widget of Provider in Riverpod?</p>
  <p>The use case is to create a provider only when a page whose parent widget is ChangeNotifierProvider/or a page that has ChangeNotifierProvider in its widget tree has been pushed unto the Navigator stack using <code>create</code>. I would like the provider to be automatically disposed when the page is popped and the ChangeNotifierProvider widget is removed from the widget tree just like in Provider.</p>