flutter firebase StreamBuilder iteams repeating

Question

StreamBuilder<QuerySnapshot>(
  stream:  chatRef
    .where('ids', arrayContainsAny: [FirebaseAuth.instance.currentUser!.uid])
    .orderBy('lastTime', descending: true)
    .snapshots(),
    builder: (context,snapshot ){
      if (snapshot.hasData) {
        final mess = snapshot.data!.docs;
  
        final List<ChatList> messages= mess.map((e) => ChatList.fom( e , FirebaseAuth.instance.currentUser!.uid)).toList() ;
  
      // }
        return Column(
          children: [
            Expanded(
              child: ListView(
  
                // controller: scr,
                children: messages,
              ),
            ),
          ],
        );
      } else {
        return Column(
          children: [
            Expanded(
              child: ListView(
                children: [
                  Center(
                    child: SpinKitCubeGrid(
                      color: Colors.green,
                    ),
                  ),
                ],
              ),
            ),
          ],
        );
      }
    })