code: func RawCombinedOutputNative(args ...string) error {
  	if output, err := raw(args...); err != nil || len(output) != 0 {
  		return fmt.Errorf("%s (%v)", string(output), err)
  	}
  	return nil
  }
docs: // RawCombinedOutputNative behave as RawCombinedOutput with the difference it
  // will always invoke `iptables` binary