I'm trying to use queue api with cron, everything seems work but drupal does not enter on the "worker" function. I don't understand why..

<?php 

/**
 * Implements hook_cron_queue_info().
 */
function monitor_import_cron_queue_info() {
  $queue['monitor_import_queue'] = array(
    'worker callback' => 'monitor_import_queue_worker',
    'time' => 10,
  );
  return $queue;
}

/**
 * Implements hook_cron().
 */
function monitor_import_cron() {

  $call = new MyWS();
  $params = new getSoggettoView();
  $params->limit = '10'; //$limit;
  $params->offset = '0';
  $results = $call->getSoggettoView($params);
  $items = $results->return;
  $queue = DrupalQueue::get('monitor_import_queue'); // grab queue
  $queue->createQueue(); // initialize
  foreach ($items as $item) {
    $queue->createItem($item);
  }
}

/**
 * Worker callback
 *
 * @see mymodule_cron_queue_info().
 */
function monitor_import_queue_worker($item) {
  $a = 1;
}

I'm trying to use queue api with cron, everything seems work but drupal does not enter on the "worker" function. The problem there is only if I enable Elysia Cron (and I've to enable it..)

<?php 

/**
 * Implements hook_cron_queue_info().
 */
function monitor_import_cron_queue_info() {
  $queue['monitor_import_queue'] = array(
    'worker callback' => 'monitor_import_queue_worker',
    'time' => 10,
  );
  return $queue;
}

/**
 * Implements hook_cron().
 */
function monitor_import_cron() {

  $call = new MyWS();
  $params = new getSoggettoView();
  $params->limit = '10'; //$limit;
  $params->offset = '0';
  $results = $call->getSoggettoView($params);
  $items = $results->return;
  $queue = DrupalQueue::get('monitor_import_queue'); // grab queue
  $queue->createQueue(); // initialize
  foreach ($items as $item) {
    $queue->createItem($item);
  }
}

/**
 * Worker callback
 *
 * @see mymodule_cron_queue_info().
 */
function monitor_import_queue_worker($item) {
  $a = 1;
}