code: public void nextRangeMaximumAvailable()
      {
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.entry(tc, "nextRangeMaximumAvailable");
  
          synchronized (_globalUniqueLock) 
          {
              _globalUniqueThreshold = _globalUniqueLimit + _midrange;
              _globalUniqueLimit     = _globalUniqueLimit + _range;
          }
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.exit(tc, "nextRangeMaximumAvailable");
      }
docs: Callback to inform the generator that the current range of available
  unique keys has now grown.