code: int findPossibleMarker(char[] chars, int limit) {
      search:
      for (int i = 0; true; i++) {
        for (int m = 0; m < marker.length() && i + m < limit; m++) {
          if (chars[i + m] != marker.charAt(m)) {
            continue search;
          }
        }
        return i;
      }
    }
docs: Returns the index of marker in {@code chars}, stopping at {@code limit}.
  Should the chars end with a prefix of marker, the offset of that prefix
  is returned.