code: func parse(xlog xlog.Position) (res [2]int, err error) {
  	parts := strings.SplitN(string(xlog), "/", 2)
  	if len(parts) != 2 {
  		err = fmt.Errorf("malformed xlog position %q", xlog)
  		return
  	}
  
  	res[0], err = parseHex(parts[0])
  	if err != nil {
  		return
  	}
  	res[1], err = parseHex(parts[1])
  
  	return
  }
docs: // parse takes an xlog position emitted by postgres and returns an array of two
  // integers representing the filepart and offset components of the xlog
  // position. This is an internal representation that should not be exposed
  // outside of this package.