docs: private int getSeenMessageCount()
     {
        if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.entry(this, tc,"getSeenMessageCount");
        
        int seenMsgs = 0;
        for (int x = 0; x < nextIndex; x++)
        {
           if (messages[x] != null) seenMsgs++;
        }
        
        if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.exit(this, tc,"getSeenMessageCount", ""+seenMsgs);
        return seenMsgs;
     }