func (p *addrParser) skipCFWS() bool {
	p.skipSpace()

	for {
		if !p.consume('(') {
			break
		}

		if _, ok := p.consumeComment(); !ok {
			return false
		}

		p.skipSpace()
	}

	return true
}

func (p *addrParser) consumeComment() (string, bool) {
	// '(' already consumed.
	depth := 1

	var comment string
	for {
		if p.empty() || depth == 0 {
			break