public void LoadData(System.Action <GameSaveData> OnLoadCompleted)
        {
            CreateDirectoryIfNeeded();

            string fileContents = null;

            if (File.Exists(fullPath))
            {
                fileContents = File.ReadAllText(fullPath);
            }

            GameSaveData saveData;

            if (!string.IsNullOrEmpty(fileContents))
            {
                saveData = JsonUtility.FromJson <GameSaveData>(fileContents);
            }
            else
            {
                saveData = new GameSaveData()
                {
                    Value = ""
                }
            };

            OnLoadCompleted?.Invoke(saveData);
        }
        public void SaveData(GameSaveData saveData)
        {
            CreateDirectoryIfNeeded();

            string fileContents = JsonUtility.ToJson(saveData);

            File.WriteAllText(fullPath, fileContents);
        }