// hi exclusive (valid registers are lo through hi-1).
func RegisterRegister(lo, hi int, Rconv func(int) string) {
	regSpace = append(regSpace, regSet{lo, hi, Rconv})
}

func Rconv(reg int) string {
	if reg == REG_NONE {
		return "NONE"
	}
	for i := range regSpace {
		rs := &regSpace[i]
		if rs.lo <= reg && reg < rs.hi {
			return rs.Rconv(reg)
		}
	}
	return fmt.Sprintf("R???%d", reg)
}

	Rtt                  uint32
	Rttvar               uint32
	Snd_ssthresh         uint32
	Snd_cwnd             uint32
	Advmss               uint32
	Reordering           uint32
	Rcv_rtt              uint32
	Rcv_space            uint32
	Total_retrans        uint32
	Pacing_rate          uint64
	Max_pacing_rate      uint64
	Bytes_acked          uint64
	Bytes_received       uint64
	Segs_out             uint32