private static void serializeObject(MySaveObject obj)
        {
            Stream stream = File.Open(file, FileMode.Create);
            BinaryFormatter bformatter = new BinaryFormatter();

            //write obj to file
            bformatter.Serialize(stream, obj);
            stream.Close();
        }
        private static void start()
        {
            //serialize the obj
            MySaveObject obj = new MySaveObject();
            obj.jsonString = "{'name':'tom'}";
            serializeObject(obj);

            //deserialize and read back the obj that has the saved data
            MySaveObject objNew = deserializeObject();
            Console.WriteLine(objNew.jsonString);

            //another step if want
            //read the saved data and convert the saved jsonString from obj into entity
            Entity obj2 = JsonConvert.DeserializeObject<Entity>(obj.jsonString);
            Console.WriteLine(obj2.name);
        }