bool array to playerprefs

In this case, I use serializable and JsonUtility. But this is slow.

     [System.Serializable]
     class BoolArray { public List<bool> bools = new List<bool>(); };
     void SaveBoolArray(string key, BoolArray boolArray)
     {
         var str = JsonUtility.ToJson(boolArray);
         PlayerPrefs.SetString(key, str);
     }
     BoolArray LoadBoolArray(string key)
     {
         var str = PlayerPrefs.GetString(key);
         return JsonUtility.FromJson<BoolArray>(str);
     }