docs: public int getInMemoryDataSize()
      {
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.entry(this, tc, "getInMemoryDataSize");
          int dataSize;
  
          // If tuning has requested return the size of the message we reference,
          // then delegate to the message. Otherwise call our parent to get a
          // (small) default size.
          if (_sizeRefsByMsgSize)
          {
              try
              {
                  dataSize = getReferredItem().getInMemoryDataSize();
              }
              catch (SevereMessageStoreException e)
              {
                  com.ibm.ws.ffdc.FFDCFilter.processException(e,"com.ibm.ws.sib.msgstore.ItemReference.getInMemoryDataSize","244",this);
                  // After FFDCing anything nasty, fall back to the standard answer
                  dataSize = super.getInMemoryDataSize();
              }
          }
          else
          {
              dataSize = super.getInMemoryDataSize();
          }
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.exit(this, tc, "getInMemoryDataSize",  dataSize);
          return dataSize;
      }