code: func (s Storage) expirationDuration(c context.Context) time.Duration {
  	if info.IsDevAppServer(c) {
  		return time.Second
  	}
  	return time.Minute
  }
docs: // expirationDuration returns how long to hold settings in memory cache.
  //
  // One minute in prod, one second on dev server (since long expiration time on
  // dev server is very annoying).