feat(bloc_helper): add wrap feature

packages/wyatt_bloc_helper/lib/src/bloc_base/bloc_base_consumer_screen.dart

@@ -36,6 +36,11 @@ abstract class BlocBaseConsumerScreen<B extends BlocBase<S>, S extends Object>
   /// must return a widget.
   Widget onBuild(BuildContext context, S state);
 
+  /// The [onWrap] function which will be invoked on each widget build.
+  /// The [onWrap] takes the `BuildContext`
+  /// Used to wrap which depends on the state.
+  Widget onWrap(BuildContext context, Widget child) => child;
+
   /// Takes the `BuildContext` along with the `state`
   /// and is responsible for executing in response to `state` changes.
   void onListen(BuildContext context, S state) {}
@@ -45,6 +50,6 @@ abstract class BlocBaseConsumerScreen<B extends BlocBase<S>, S extends Object>
         listenWhen: shouldListenWhen,
         listener: onListen,
         buildWhen: shouldBuildWhen,
-        builder: onBuild,
+        builder: (context, state) => onWrap(context, onBuild(context, state)),
       );
 }