trying to post with a user name

  //get collection posts
  final CollectionReference posts = FirebaseFirestore.instance.collection("User posts");
  Future<void> getUsername() async {
    try {
      final DocumentSnapshot docRef = await FirebaseFirestore.instance
          .collection("Users")
          .doc("${user!.email}").get();

      if (docRef.exists) {
        final map = docRef.data() as Map<String, dynamic>;
        String name = map['username'];
        print(name); //or add your own logic to handle the user's info
      } else {
        print("document with id : \"${user!.email}\" does not exists");
      }

    } catch (e) {
      print(e.toString());
      rethrow;
    }
  }
  //post the [posts]

  Future<void> addPosts(String message, String title, fileurl)  {

    final data = getUsername();
    return posts.add({
    'posttitle': title,
    'UserEmail': user!.email,
    'postMessage': message,
    'TimeStamp': Timestamp.now(),
    'Likes': [],
    'comments': [],
    'postfile': fileurl,
    });

  }