code: private synchronized void onDriverRestartCompleted(final boolean isTimedOut) {
      if (this.state != DriverRestartState.COMPLETED) {
        final Set<String> outstandingEvaluatorIds = getOutstandingEvaluatorsAndMarkExpired();
        driverRuntimeRestartManager.informAboutEvaluatorFailures(outstandingEvaluatorIds);
  
        this.state = DriverRestartState.COMPLETED;
        final DriverRestartCompleted driverRestartCompleted = new DriverRestartCompletedImpl(
            System.currentTimeMillis(), isTimedOut);
  
        for (final EventHandler<DriverRestartCompleted> serviceRestartCompletedHandler
            : this.serviceDriverRestartCompletedHandlers) {
          serviceRestartCompletedHandler.onNext(driverRestartCompleted);
        }
  
        for (final EventHandler<DriverRestartCompleted> restartCompletedHandler : this.driverRestartCompletedHandlers) {
          restartCompletedHandler.onNext(driverRestartCompleted);
        }
  
        LOG.log(Level.FINE, "Restart completed. Evaluators that have not reported back are: " + outstandingEvaluatorIds);
      }
  
      restartCompletedTimer.cancel();
    }
docs: Sets the driver restart status to be completed if not yet set and notifies the restart completed event handlers.