CronController.php

<?php

namespace Drupal\system;

use Drupal\Core\Controller\ControllerBase;
use Drupal\Core\CronInterface;
use Symfony\Component\HttpFoundation\Response;

/**
 * Controller for Cron handling.
 */
class CronController extends ControllerBase {
    
    /**
     * The cron service.
     *
     * @var \Drupal\Core\CronInterface
     */
    protected $cron;
    
    /**
     * Constructs a CronController object.
     *
     * @param \Drupal\Core\CronInterface $cron
     *   The cron service.
     */
    public function __construct(CronInterface $cron) {
        $this->cron = $cron;
    }
    
    /**
     * Run Cron once.
     *
     * @return \Symfony\Component\HttpFoundation\Response
     *   A Symfony response object.
     */
    public function run() {
        $this->cron
            ->run();
        // HTTP 204 is "No content", meaning "I did what you asked and we're done."
        return new Response('', 204);
    }
    
    /**
     * Run cron manually.
     *
     * @return \Symfony\Component\HttpFoundation\RedirectResponse
     *   A Symfony direct response object.
     */
    public function runManually() {
        if ($this->cron
            ->run()) {
            $this->messenger()
                ->addStatus($this->t('Cron ran successfully.'));
        }
        else {
            $this->messenger()
                ->addError($this->t('Cron run failed.'));
        }
        return $this->redirect('system.status');
    }

}