code: func UnescapeValue(s string) (string, error) {
  	// if there's no escaping or special characters, just return to avoid allocation
  	if !strings.ContainsAny(s, `\,=`) {
  		return s, nil
  	}
  
  	v := bytes.NewBuffer(make([]byte, 0, len(s)))
  	inSlash := false
  	for _, c := range s {
  		if inSlash {
  			switch c {
  			case '\\', ',', '=':
  				// omit the \ for recognized escape sequences
  				v.WriteRune(c)
  			default:
  				// error on unrecognized escape sequences
  				return "", InvalidEscapeSequence{sequence: string([]rune{'\\', c})}
  			}
  			inSlash = false
  			continue
  		}
  
  		switch c {
  		case '\\':
  			inSlash = true
  		case ',', '=':
  			// unescaped , and = characters are not allowed in field selector values
  			return "", UnescapedRune{r: c}
  		default:
  			v.WriteRune(c)
  		}
  	}
  
  	// Ending with a single backslash is an invalid sequence
  	if inSlash {
  		return "", InvalidEscapeSequence{sequence: "\\"}
  	}
  
  	return v.String(), nil
  }
docs: // UnescapeValue unescapes a fieldSelector value and returns the original literal value.
  // May return the original string if it contains no escaped or special characters.