docs: public long getCompletedPrefix()
    {
      if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
        SibTr.entry(tc, "getCompletedPrefix");
      if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
        SibTr.exit(tc, "getCompletedPrefix", Long.valueOf(_targetStream.getCompletedPrefix()));
  
      return _targetStream.getCompletedPrefix();
    }