func (req *ReqV2) Len() int {
	return SizeofReqV2
}
Len is provided for json serialization?
package inetdiag
import (
	"encoding/binary"
	"errors"
	"fmt"
	"log"
	"net"
	"runtime"
	"unsafe"
	"github.com/m-lab/go/anonymize"
)
const (
	SOCK_DIAG_BY_FAMILY = 20  
)
var (
	ErrBadPid = errors.New("bad PID, can't listen to NL socket")
	ErrBadSequence = errors.New("bad sequence number, can't interpret NetLink response")
	ErrBadMsgData = errors.New("bad message data from netlink message")
)
type ReqV2 struct {
	SDiagFamily   uint8
	SDiagProtocol uint8
	IDiagExt      uint8
	Pad           uint8
	IDiagStates   uint32
	ID            LinuxSockID
}
const SizeofReqV2 = int(unsafe.Sizeof(ReqV2{}))  
func (req *ReqV2) Serialize() []byte {
	return (*(*[SizeofReqV2]byte)(unsafe.Pointer(req)))[:]
}