title: Flutter problem with ChangeNotifierProxyProvider create
body: <p>Since builder method of ChangeNotifierProxyProvider in flutter is deprecated i'm tring to implement create and update new methods of provider 4.</p>
  
  <p>I need the main Auth Provider called User Provider inside another Provider(ContoProvider) on create but I have runtime error with Provider not found. All this provider are inside a Multiprovider in the main.dart file so the at the top of widget chain.</p>
  
  <p>Probably this isn't the right method to pass the provider but i need in the create because i use it immediately</p>
  
  <pre><code>return MultiProvider(
    providers: [
      ChangeNotifierProvider&lt;UserProvider&gt;(
        create: (_) =&gt; UserProvider.init(),
  
      ),
      ChangeNotifierProxyProvider&lt;UserProvider, ContoProvider&gt;(
        create: (_) =&gt; ContoProvider.init(
          Provider.of&lt;UserProvider&gt;(context, listen: false),
        ),
        update: (_,  userProvider,  contoProvider) =&gt;
            contoProvider..update(userProvider),
      ),
    ],child:..
  </code></pre>