Need explanation about util.Buffer

[shi0rik0]

I can't figure out why util.Buffer should exist. Take the ipv4 for example.

type IPv4 struct {
	Version        uint8 //4-bits
	IHL            uint8 //4-bits
	DSCP           uint8 //6-bits
	ECN            uint8 //2-bits
	Length         uint16
	Id             uint16
	Flags          uint16 //3-bits
	FragmentOffset uint16 //13-bits
	TTL            uint8
	Protocol       uint8
	Checksum       uint16
	NWSrc          net.IP
	NWDst          net.IP
	Options        util.Buffer
	Data           util.Message
}

Why should the type of "Options" field be util.Buffer?

[shi0rik0]

I think a simple []byte is enough for "Options". If we want to support Marshal and Unmarshal on it, we can just let it be util.Message.