code: func (dbi *dbItem) writeSetTo(buf []byte) []byte {
  	if dbi.opts != nil && dbi.opts.ex {
  		ex := dbi.opts.exat.Sub(time.Now()) / time.Second
  		buf = appendArray(buf, 5)
  		buf = appendBulkString(buf, "set")
  		buf = appendBulkString(buf, dbi.key)
  		buf = appendBulkString(buf, dbi.val)
  		buf = appendBulkString(buf, "ex")
  		buf = appendBulkString(buf, strconv.FormatUint(uint64(ex), 10))
  	} else {
  		buf = appendArray(buf, 3)
  		buf = appendBulkString(buf, "set")
  		buf = appendBulkString(buf, dbi.key)
  		buf = appendBulkString(buf, dbi.val)
  	}
  	return buf
  }
docs: // writeSetTo writes an item as a single SET record to the a bufio Writer.