code: @CommandArgument
    public void setcpus(int numberOfCpus) {
      if (worker == null) {
        System.err.println("Worker not running.");
        return;
      }
      int availableCpus = Runtime.getRuntime().availableProcessors();
      if (numberOfCpus <= 0 || numberOfCpus > availableCpus) {
        numberOfCpus = availableCpus;
      }
      System.out.printf("Setting number of CPUs to %d\n", numberOfCpus);
      worker.setMaxWorkers(numberOfCpus);
    }
docs: Sets the maximum number of concurrent workers.
  @param numberOfCpus The number of CPUs to use (zero to use all available
  CPUs on the machine).