Flutter/Dart/Firestore :如何创建子集合并将数据添加到Firestore？

import 'package:cloud_firestore/cloud_firestore.dart';

final FirebaseFirestore firestore = FirebaseFirestore.instance;

void createSubcollection() async {
  // 获取对应的集合引用
  CollectionReference mainCollection = firestore.collection('main_collection');

  // 创建子集合
  DocumentReference subCollection = mainCollection.doc('document_id').collection('sub_collection').doc();

  // 添加数据到子集合
  await subCollection.set({
    'field1': 'value1',
    'field2': 'value2',
  });
}