upload method
Implementation
Future<QBFile?> upload(String url, {bool public = false}) async {
Map<String, Object> data = Map();
data["url"] = url;
data["public"] = public;
Map<Object?, Object?> map =
await _fileModule.invokeMethod(UPLOAD_METHOD, data);
QBFile? file = QBFileMapper.mapToQBFile(map);
return file;
}