Flutter 尝试使用Firebase的动态地图时出现问题

我正在尝试使用flatter_-indications插件来处理我在Firebase中拥有的数据。该示例仅显示手动输入的静态虚拟数据，因此我尝试动态获取数据

这就是我现在拥有的。如何从用户引用中查询userId、username和profileUrl，并将其提供给数据：[]映射？他们还提到suggestionBuilder也可以使用

var data = Firestore.instance.collection('users').getDocuments();


child: FlutterMentions(
                decoration: InputDecoration(
                  contentPadding: const EdgeInsets.only(left: 8.0),
                  labelText: "Write comment here!",
                  labelStyle: TextStyle(color: Colors.grey),
                  enabledBorder: UnderlineInputBorder(
                      borderSide: BorderSide(color: Colors.grey)),
                  focusedBorder: UnderlineInputBorder(
                      borderSide: BorderSide(color: Colors.grey)),
                ),
                style: TextStyle(color: Colors.black),
                keyboardType: TextInputType.multiline,
                suggestionPosition: SuggestionPosition.Top,
                maxLines: null,
                minLines: 1,
                mentions: [
                  Mention(
                    trigger: "@",
                    style: TextStyle(color: Colors.blue),
                    data: [
                      {
                        "id": "61as61fsa",
                        "display": "fayeedP",
                        "photo":
                            "https://images.pexels.com/photos/220453/pexels-photo-220453.jpeg"
                      },
                      {
                        "id": "61asasgasgsag6a",
                        "display": "khaled",
                        "photo":
                            "https://images.pexels.com/photos/220453/pexels-photo-220453.jpeg",
                      },
                    ],
                  ),
                ],
                trailing: [
                  OutlineButton(
                    onPressed: saveComment,
                    borderSide: BorderSide.none,
                    child: Text(
                      "Publish",
                      style: TextStyle(
                          color: Colors.blue, fontWeight: FontWeight.bold),
                    ),
                  ),
                ],
              ),

如果我遗漏了什么重要的东西，请告诉我。非常感谢您的帮助。谢谢