code: public void backoffActualHighWatermark() {
      JsonElement lowWatermark = this.workUnit.getLowWatermark();
      if (lowWatermark == null) {
        return;
      }
      setProp(ConfigurationKeys.WORK_UNIT_STATE_ACTUAL_HIGH_WATER_MARK_KEY, lowWatermark.toString());
    }
docs: Backoff the actual high watermark to the low watermark returned by {@link WorkUnit#getLowWatermark()}.