在appbar中显示'Error in firebase‘的Flutter web

import 'package:flutter/material.dart';
import 'package:firebase/firebase.dart' as firebase;

void main() {
  firebase.initializeApp(
    apiKey: 'YOUR_API_KEY',
    authDomain: 'YOUR_AUTH_DOMAIN',
    databaseURL: 'YOUR_DATABASE_URL',
    projectId: 'YOUR_PROJECT_ID',
    storageBucket: 'YOUR_STORAGE_BUCKET',
    messagingSenderId: 'YOUR_MESSAGING_SENDER_ID',
  );
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Firebase Error',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: Scaffold(
        appBar: AppBar(
          title: Text('Error in firebase'),
        ),
        body: Center(
          child: RaisedButton(
            child: Text('Trigger Error'),
            onPressed: () {
              // 触发Firebase错误
              firebase.database().ref('non_existent_path').once('value');
            },
          ),
        ),
      ),
    );
  }
}