Flutter: slivers+StreamBuilder

main.dart

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);
  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  Stream<int> stream;

  @override
  void initState() {
    stream = Stream.periodic(Duration(seconds: 1), (int i) => i);
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        body: CustomScrollView(slivers: <Widget>[
          SliverAppBar(
            title: Text('Sliver App Bar'),
            floating: true,
            snap: true,
            bottom: PreferredSize(
              preferredSize: const Size.fromHeight(90.0),
              child: Text('dddd'),
            ),
          ),
          StreamBuilder(
            stream: stream,
            builder: (context, snapshot) => SliverList(
             delegate: SliverChildBuilderDelegate(
                (context, index) => ListTile(title: Text(snapshot.data.toString())),
                childCount: snapshot.hasData ? 1 : 0,
             )
            )
          )
        ])
    );
  }
}

thank you so much for this!!!