Crash reproduction for flutter bug

main.dart

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      title: 'Flutter Demo',
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatelessWidget {
  const MyHomePage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('It will crash after 5 seconds')),
      body: CustomScrollView(
        slivers: [
          FutureBuilder<String>(
            future: Future.delayed(const Duration(seconds: 5), () => "Crash"),
            builder: (context, snapshot) {
              if (!snapshot.hasData) {
                return const SliverToBoxAdapter(
                  child: SizedBox(),
                );
              }
              return SliverList(
                delegate: SliverChildListDelegate.fixed([
                  Text(snapshot.data!),
                ]),
              );
            },
          ),
        ],
      ),
    );
  }
}