code: public JsonElement getExpectedHighWatermark() {
      return JSON_PARSER.parse(getProp(ConfigurationKeys.WATERMARK_INTERVAL_VALUE_KEY)).getAsJsonObject()
          .get(WatermarkInterval.EXPECTED_HIGH_WATERMARK_TO_JSON_KEY);
    }
docs: Get the expected high {@link Watermark} as a {@link JsonElement}.
  
  @return a {@link JsonElement} representing the expected high {@link Watermark}.