在flutter应用程序中如何在firestore数据库的文档中添加文档Id

dependencies:
  firebase_core: ^1.0.0
  cloud_firestore: ^2.0.0

import 'package:firebase_core/firebase_core.dart';
import 'package:cloud_firestore/cloud_firestore.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  runApp(MyApp());
}

import 'package:cloud_firestore/cloud_firestore.dart';

void addDocumentWithId() {
  FirebaseFirestore.instance.collection('users').doc('documentId').set({
    'name': 'John Doe',
    'email': 'johndoe@example.com',
  });
}

import 'package:cloud_firestore/cloud_firestore.dart';

void addDocumentWithAutoId() {
  FirebaseFirestore.instance.collection('users').add({
    'name': 'John Doe',
    'email': 'johndoe@example.com',
  });
}