Future<void> downloadFile(String name, String uuid) async {
    final _localPath = (await findLocalPath()) + Platform.pathSeparator + 'Download';
    final savedDir = Directory(_localPath);
    bool hasExisted = savedDir.existsSync();
    if (!hasExisted) {
      savedDir.createSync();
    }
    await Dio().download(
      '${url}',
      '$_localPath/$name',
      options: Options(
          method: 'POST',
          headers: <String, dynamic>{'Content-Type': 'application/json'}),
      onReceiveProgress: (count, total) {
        downloadingMessages[uuid] = count / total;
        notifyListeners();
      },
    );
    downloadingMessages.remove(uuid);
    downloadedMessages[uuid] = '$_localPath/$name';
    notifyListeners();
  }