title: Flutter "ChangeNotifierProxyProvider have an error. error: "The named parameter 'builder' isn't defined. "
body: <p>main.dart file ChangeNotifierProxyProvider having issues builder method is not defined.</p>
  
  <pre><code> ChangeNotifierProxyProvider&lt;Auth, Orders&gt;(
        builder: (ctx, auth, previousOrders) =&gt; Orders(
          auth.token,
          auth.userId,
          previousOrders == null ? [] : previousOrders.orders,
        ),
      ),
  </code></pre>