code: private static byte[] print(final RsJson.Source src) throws IOException {
          final ByteArrayOutputStream baos = new ByteArrayOutputStream();
          try (JsonWriter writer = Json.createWriter(baos)) {
              writer.write(src.toJson());
          }
          return baos.toByteArray();
      }
docs: Print JSON.
  @param src Source
  @return JSON
  @throws IOException If fails