code: func NewRule() *Rule {
  	return &Rule{
  		SuppressIfgroup:   -1,
  		SuppressPrefixlen: -1,
  		Priority:          -1,
  		Mark:              -1,
  		Mask:              -1,
  		Goto:              -1,
  		Flow:              -1,
  	}
  }
docs: // NewRule return empty rules.