Running a queue worker without using cron tasks I implemented hook_queue_info() with the following code.

function ecc_general_queue_info() {
  $queues = array();
  $queues['adding_checklist'] = array(
    'worker callback' =&gt; '_ecc_general_apply_queue',
    'time' =&gt; 60,
  );
  return $queues;
}


I create  items for the queue with the following code.

$queue_factory = \Drupal::service('queue');
$queue = $queue_factory-&gt;get('adding_checklist');
$queue-&gt;createItem([$node, 'insert']);


The callback function is the following.

function _ecc_general_apply_queue($item) {
  // Some code here.
}


I want to run this callback for each item in the queue. How can I process the queue to execute its worker callback for each item?  

I don't want to use cron tasks for processing the queue.
Queue is processed by cron through core. You can also use Drush and Drupal Console to run queue items as well.

Drush:

drush queue:list to get the available queues.

drush queue:run to run a single item.

drush queue:delete to clear a queue.

Drupal Console:

drupal debug:queue to debug your queue.

drupal queue:run &lt;name-of-the-queue&gt; To run a single item.