In page A I use StreamBuilder to render some data,
then I push to B page using Navigator.push (A’s Stream is not stoped)

I found A’s StreamBuilder builder is still calling.

/// a complex model with lots of data
class AModel {}

class APage extends StatefulWidget {
  const APage({super.key});

  @override
  State<APage> createState() => _APageState();
}

class _APageState extends State<APage> {
  /// Data is pushed via websocket every second
  StreamController<List<AModel>> streamController =
      StreamController<List<AModel>>();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Home Page'),
      ),
      body: StreamBuilder(
          stream: streamController.stream,
          builder: (BuildContext context, snapshot) {
            print('This builder not stop after push to B Page');
            if (snapshot.data == null) {
              return const SizedBox.shrink();
            }
            final List<AModel> list = snapshot.data!;
            return ListView.builder(
              itemCount: list.length,
              itemBuilder: (BuildContext context, int index) {
                return ACell(model: list[index]);
              },
            );
          }),
    );
  }
}

class ACell extends StatelessWidget {
  final AModel model;
  const ACell({super.key, required this.model});

  @override
  Widget build(BuildContext context) {
    /// AModel has a complex layout. Here we use a button as an example.
    return ElevatedButton(
      onPressed: () {
        Navigator.push(
          context,
          MaterialPageRoute(builder: (context) => const SecondRoute()),
        );
      },
      child: const Text('Push'),
    );
  }
}

class BRoute extends StatelessWidget {
  const BRoute({super.key});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('B Page'),
      ),
      body: Center(
        child: ElevatedButton(
          onPressed: () {
            Navigator.pop(context);
          },
          child: const Text('Go back!'),
        ),
      ),
    );
  }
}

Questions：

1. After pushing to page B, the data of A is still refreshing. Does this have any impact on performance?
2. If so, do I have to turn A’s Stream off manually when pushing to B?
3. Flutter doesn’t have a method like ViewDisappear, so how can I stop the stream?
4. Is there any better way？

Thank you very much!