docs: private static void printStartStopTimes() {
          final long start = System.currentTimeMillis();
  
          System.err.println("Start at " + new Date());
  
          Thread hook = new Thread() {
              @Override
              public void run() {
                  long timePassed = System.currentTimeMillis() - start;
                  System.err.println("Stop at " + new Date() + ", execution time = " + timePassed + " ms");
              }
          };
          Runtime.getRuntime().addShutdownHook(hook);
      }