code: func (m *MemoryStorage) UpdateSetting(c context.Context, key string, value json.RawMessage, who, why string) error {
  	m.lock.Lock()
  	defer m.lock.Unlock()
  	if m.values == nil {
  		m.values = make(map[string]*json.RawMessage, 1)
  	}
  	cpy := append(json.RawMessage(nil), value...)
  	m.values[key] = &cpy
  	return nil
  }
docs: // UpdateSetting updates a setting at the given key.