code: func QuoteMeta(s string) string {
  	b := make([]byte, 2*len(s))
  
  	// A byte loop is correct because all metacharacters are ASCII.
  	j := 0
  	for i := 0; i < len(s); i++ {
  		if special(int(s[i])) {
  			b[j] = '\\'
  			j++
  		}
  		b[j] = s[i]
  		j++
  	}
  	return string(b[0:j])
  }
docs: // QuoteMeta returns a string that quotes all regular expression metacharacters
  // inside the argument text; the returned string is a regular expression matching
  // the literal text.  For example, QuoteMeta(`[foo]`) returns `\[foo\]`.