code: func (i *impl) isRetryable(g status.Group, c int32) bool {
  	for group, codes := range i.opts.RetryableCodes {
  		if g != group {
  			continue
  		}
  		for _, code := range codes {
  			if status.Code(c) == code {
  				return true
  			}
  		}
  	}
  	return false
  }
docs: // isRetryable determines if the given status is configured to be retryable