code: public String render(Reader in, RenderContext context) throws IOException {
      StringBuffer buffer = new StringBuffer();
      BufferedReader inputReader = new BufferedReader(in);
      String line;
      while ((line = inputReader.readLine()) != null) {
          buffer.append(line);
      }
      return render(buffer.toString(), context);
   }
docs: Render an input with text markup from a Reader and write the result to a writer
  
  @param in Reader to read the input from
  @param context Special context for the render engine, e.g. with
  configuration information