"Read Data from Firebase", not working after update 2.8.1 - firebase

Question

Solution
Added code before return
if (!snapshot.hasData) {
return const Scaffold(
body: Center(
child: CircularProgressIndicator(
color: Colors.red,
)),
);
}
important! - if (!snapshot.hasData)
I try show data from FireBase, I have DB on Firestore.
I updated today Flutter (2.8.0 -> 2.8.1) , code worked before update
My code
import 'package:cloud_firestore/cloud_firestore.dart';
class FireService extends StatefulWidget {
#override
_FireServiceState createState() => _FireServiceState();
}
class _FireServiceState extends State<FireService> {
final Stream<QuerySnapshot> _usersStream = FirebaseFirestore.instance
.collection('chats/uHdJ4WvHjvphsBUpb9yk/visits')
.snapshots();
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Visits'),
),
body: StreamBuilder(
stream: _usersStream,
builder:
(BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
return ListView(
children: snapshot.data!.docs.map((DocumentSnapshot document) {
Map<String, dynamic> data =
document.data()! as Map<String, dynamic>;
return Card(
child: ListTile(
title: Text(
data['company'],
style: TextStyle(fontSize: 19, color: Colors.black),
),
subtitle: Text(
data['number_visit'].toString(),
),
leading: Icon(
Icons.local_offer,
size: 40,
color: Colors.red,
),
),
);
}).toList(),
);
}),
);
}
}
After starting an error occurs
enter image description here
Please, write a new code so I understand the error. Thanks
UPD 1.
I tried an option
children: snapshot.data?.docs.map((DocumentSnapshot document) {
a new mistake - the whole block of code with a red line
enter image description here

Answer 1

Your line snapshot.data!.docs.map should use the nullish coalescing instead of the !.
The line should be:
snapshot.data?.docs.map
data?. will gracefully break if data is null