FLUTTER，FIRESTORE :我有一个streambuilder，它从collection..how中的所有文档中返回某个字段，我要添加查询吗？

CollectionReference usersRef = FirebaseFirestore.instance.collection('users');

Query query = usersRef.where('age', isGreaterThanOrEqualTo: 18);

StreamBuilder<QuerySnapshot>(
  stream: query.snapshots(),
  builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
    if (snapshot.hasError) {
      return Text('Error: ${snapshot.error}');
    }

    if (snapshot.connectionState == ConnectionState.waiting) {
      return Text('Loading...');
    }

    // 处理查询结果
    List<DocumentSnapshot> documents = snapshot.data.docs;
    // 进一步处理文档数据
    // ...

    return Text('Query result: ${documents.length} documents');
  },
);