docs: public long getPerInstanceUniqueValue()
      {
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.entry(tc, "getPerInstanceUniqueValue");
  
          long retval;
  
          synchronized(_instanceUniqueLock)
          {
              retval = _instanceUnique--;
          }
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.exit(tc, "getPerInstanceUniqueValue", "return="+retval);
          return retval;
      }