code: func (r *Reference) refreshValue() {
  	if value, err := r.initializer(nil); err != nil {
  		logger.Warnf("Error - initializer returned error: %s. Will retry again later", err)
  	} else {
  		r.set(value)
  	}
  }
docs: // refreshValue is an expiration handler that calls the
  // initializer and, if the initializer was successful, resets
  // the reference with the new value.
  // Note: This function is invoked from inside a write
  // lock so there's no need to lock