code: func (b Ethernet) Encode(e *EthernetFields) {
  	binary.BigEndian.PutUint16(b[ethType:], uint16(e.Type))
  	copy(b[srcMAC:][:EthernetAddressSize], e.SrcAddr)
  	copy(b[dstMAC:][:EthernetAddressSize], e.DstAddr)
  }
docs: // Encode encodes all the fields of the ethernet frame header.