A Storage class which implement Key Value Store
상속: KVStore
 public string GetValue(string key, ApplicationSettingsMode mode)
 {
     var kvStore = new PlayerPreferenceKVStore();
     return kvStore.Get(key);
 }
 public void RemoveValue(string key, ApplicationSettingsMode mode)
 {
     var kvStore = new PlayerPreferenceKVStore();
     kvStore.Clear(key);
 }
 public void SetValue(string key, string value, ApplicationSettingsMode mode)
 {
     var kvStore = new PlayerPreferenceKVStore();
     kvStore.Put(key, value);
 }