Name  string `xml:"Name"`
	Value string `xml:"Value"`
}

func (filter FilterRule) isEmpty() bool {
	return filter.Name == "" && filter.Value == ""
}

// MarshalXML implements a custom marshaller to support `omitempty` feature.
func (filter FilterRule) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
	if filter.isEmpty() {
		return nil
	}
	type filterRuleWrapper FilterRule