code: public static HtmlStreamRenderer create(
        StringBuilder output, Handler<? super String> badHtmlHandler) {
      // Propagate since StringBuilder should not throw IOExceptions.
      return create(output, Handler.PROPAGATE, badHtmlHandler);
    }
docs: Factory.
  @param output the buffer to which HTML is streamed.
  @param badHtmlHandler receives alerts when HTML cannot be rendered because
  there is not valid HTML tree that results from that series of calls.
  E.g. it is not possible to create an HTML {@code <style>} element whose
  textual content is {@code "</style>"}.