code: public static String formatInput(ReplaceableString input,
                                       Transliterator.Position pos) {
          StringBuffer appendTo = new StringBuffer();
          formatInput(appendTo, input, pos);
          return android.icu.impl.Utility.escape(appendTo.toString());
      }
docs: For debugging purposes; format the given text in the form
  aaa{bbb|ccc|ddd}eee, where the {} indicate the context start
  and limit, and the || indicate the start and limit.