code: func (t *tokenWithProvider) refreshTokenWithRetries(ctx context.Context, prev, base *internal.Token) (tok *internal.Token, err error) {
  	err = retry.Retry(ctx, transient.Only(retryParams), func() error {
  		tok, err = t.provider.RefreshToken(ctx, prev, base)
  		return err
  	}, nil)
  	return
  }
docs: // refreshTokenWithRetries calls providers' RefreshToken(...) retrying on
  // transient errors a bunch of times.