code: private static void beginRRULE(Writer writer, int month) throws IOException {
          writer.write(ICAL_RRULE);
          writer.write(COLON);
          writer.write(ICAL_FREQ);
          writer.write(EQUALS_SIGN);
          writer.write(ICAL_YEARLY);
          writer.write(SEMICOLON);
          writer.write(ICAL_BYMONTH);
          writer.write(EQUALS_SIGN);
          writer.write(Integer.toString(month + 1));
          writer.write(SEMICOLON);
      }
docs: /*
  Write the beginning part of RRULE line