code: func (dbi *dbItem) writeDeleteTo(buf []byte) []byte {
  	buf = appendArray(buf, 2)
  	buf = appendBulkString(buf, "del")
  	buf = appendBulkString(buf, dbi.key)
  	return buf
  }
docs: // writeSetTo writes an item as a single DEL record to the a bufio Writer.