xlHeaderVersion = 3
	xlMetaVersion   = 2
)

type xlHeaders struct {
	versions           int
	headerVer, metaVer uint
}

func decodeXLHeaders(buf []byte) (x xlHeaders, b []byte, err error) {
	x.headerVer, buf, err = msgp.ReadUintBytes(buf)
	if err != nil {
		return x, buf, err
	}
	x.metaVer, buf, err = msgp.ReadUintBytes(buf)
	if err != nil {
		return x, buf, err
	}
	if x.headerVer > xlHeaderVersion {

		return 0, 0, 0, buf, err
	}
	metaVer, buf, err := msgp.ReadUint8Bytes(buf)
	if err != nil {
		return 0, 0, 0, buf, err
	}
	if hdrVer > xlHeaderVersion {
		return 0, 0, 0, buf, fmt.Errorf("decodeXLHeaders: Unknown xl header version %d", metaVer)
	}
	if metaVer > xlMetaVersion {
		return 0, 0, 0, buf, fmt.Errorf("decodeXLHeaders: Unknown xl meta version %d", metaVer)
	}
	versions, buf, err = msgp.ReadIntBytes(buf)