import 'package:flutter/material.dart';

void main() {
  runApp(
    MaterialApp(
      home: MyWidget(),
    ),
  );
}

class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: CustomScrollView(
        slivers: [
          const SliverAppBar(
            pinned: true,
            floating: true,
            snap: false,
            expandedHeight: 200,
            flexibleSpace: FlexibleSpaceBar(
              title: Text('Rein'),
              centerTitle: true,
            ),
          ),
          SliverList(
            delegate: SliverChildListDelegate(
              [
                const Text(
                  'Flutter\nFlutter\nFlutter\nFlutter\nFlutter\nFlutter\n',
                  style: TextStyle(fontSize: 320),
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }
}