code: @Override
      protected void setWatermarks(long nextLowWatermark, long nextHighWatermark)
      {
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              SibTr.entry(tc, "setWatermarks",
                          new Object[] { new Long(nextLowWatermark), new Long(nextHighWatermark), new Long(referenceStreamCount) });
  
          super.setWatermarks(nextLowWatermark + referenceStreamCount, nextHighWatermark + referenceStreamCount);
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              SibTr.exit(tc, "setWatermarks");
      }
docs: Include the referenceStreamCount when setting the watermarks (called by
  BaseMessageItemStream.updateWaterMarks() (which has no concept of referenceStreams)
  
  (510343)
  
  @param nextLowWatermark
  @param nextHighWatermark
  @throws SevereMessageStoreException