docs: private boolean isValidDiscriminator(String s) {
          // Could simply do this regex match, but the actual code here is about 60x faster
          // return java.util.regex.Pattern.matches("([^:./*][^:/*]*)(/[^:./*][^:/*]*)*", s);
          if (s.indexOf(':') != -1 || s.indexOf('*') != -1)
              return false;
          int last = s.length();
          if (last > 0 && (s.charAt(0) == '/' || s.charAt(0) == '.'))
              return false;
          int i = s.indexOf('/');
          while (i++ != -1) {
              if (i == last || s.charAt(i) == '/' || s.charAt(i) == '.')
                  return false;
              i = s.indexOf('/', i);
          }
          return true;
      }