code: func toError(errs []error) error {
  	if len(errs) == 0 {
  		return nil
  	}
  	if len(errs) == 1 {
  		return errs[0]
  	}
  
  	errmsgs := []string{fmt.Sprint("Multiple errors occurred in order broadcast stream: ")}
  	for _, err := range errs {
  		errmsgs = append(errmsgs, err.Error())
  	}
  	return errors.New(strings.Join(errmsgs, "\n"))
  }
docs: // toError converts []error to error