*/
  protected final String escapeSlow(String s, int index) {
    int end = s.length();

    // Get a destination buffer and setup some loop variables.
    char[] dest = Platform.charBufferFromThreadLocal();
    int destIndex = 0;
    int unescapedChunkStart = 0;

    while (index < end) {
      int cp = codePointAt(s, index, end);
      if (cp < 0) {