y/y.go
func KeyWithTs(key []byte, ts uint64) []byte {
	out := make([]byte, len(key)+8)
	copy(out, key)
	binary.BigEndian.PutUint64(out[len(key):], math.MaxUint64-ts)
	return out
}
func KeyWithTs(key []byte, ts uint64) []byte {
	out := make([]byte, len(key)+8)
	copy(out, key)
	binary.BigEndian.PutUint64(out[len(key):], math.MaxUint64-ts)
	return out
}
func KeyWithTs ( key [ ] byte , ts uint64 ) [ ] byte { out := make ( [ ] byte , len ( key ) + 8 ) copy ( out , key ) binary . BigEndian . PutUint64 ( out [ len ( key ) : ] , math . MaxUint64 - ts ) return out }
// KeyWithTs generates a new key by appending ts to key.
KeyWithTs generates a new key by appending ts to key .