[flutter] 하위 트리 내에서 동일한 태그를 공유하는 여러 영웅이 있습니다.

경로를 사용하여 한 화면에서 다른 화면으로 이동하려고합니다. 페이지의 버튼을 눌렀을 때 오류가 발생하면 경로로 이동합니다.

I/flutter ( 8790): Another exception was thrown: There are multiple heroes that share the same tag within a subtree.

코드는 다음과 같습니다.

노선 :

 <String, WidgetBuilder>{
    '/first':(BuildContext context) =>NavigatorOne() ,
    '/second':(BuildContext context) =>NavigatorTwo(),
    '/third':(BuildContext context) =>NavigatorThree(),

  },

Navigator.of(context).pushNamed('/first');
Navigator.of(context).pushNamed('/second');
Navigator.of(context).pushNamed('/third');

class NavigatorOne extends StatefulWidget {
  @override
  _NavigatorOneState createState() =>  _NavigatorOneState();
}

class _NavigatorOneState extends State<NavigatorOne> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(

      appBar: AppBar(),
      body: Container(
      color: Colors.green,
      child: RaisedButton(child: Text(' one 1'),onPressed: (){
        Navigator.of(context).pushNamed('/second');
      },),
    ),
    );
  }
}

그리고 오류 :

══╡ EXCEPTION CAUGHT BY SCHEDULER LIBRARY ╞═════════════════════════════════════════════════════════
I/flutter (21786): The following assertion was thrown during a scheduler callback:
I/flutter (21786): There are multiple heroes that share the same tag within a subtree.
I/flutter (21786): Within each subtree for which heroes are to be animated (typically a PageRoute subtree), each Hero
I/flutter (21786): must have a unique non-null tag.
I/flutter (21786): In this case, multiple heroes had the following tag: <default FloatingActionButton tag>


이 문제를 어떻게 해결합니까?