docs: public static void warmUp(GraphHopper graphHopper, int iterations) {
          GraphHopperStorage ghStorage = graphHopper.getGraphHopperStorage();
          if (ghStorage == null)
              throw new IllegalArgumentException("The storage of GraphHopper must not be empty");
  
          try {
              if (ghStorage.isCHPossible())
                  warmUpCHSubNetwork(graphHopper, iterations);
              else
                  warmUpNonCHSubNetwork(graphHopper, iterations);
          } catch (Exception ex) {
              LOGGER.warn("Problem while sending warm up queries", ex);
          }
      }