code: function size($queue = null)
      {
          $queue = $this->_normalizeQueueName($queue);
  
  
          try {
              $sql = "SELECT COUNT(*) as `count_queue` FROM `{$this->table}` WHERE `queue_name` = '$queue';";
  
              $stm = $this->conn->prepare($sql);
              $stm->execute();
              $stm->setFetchMode(\PDO::FETCH_ASSOC);
  
              $queued = $stm->fetch();
  
          } catch (\Exception $e) {
              throw new exReadError('Error While Read From MySql Client.', $e->getCode(), $e);
          }
  
          return (int) $queued['count_queue'];
      }
docs: Get Queue Size
  
  @param string $queue
  
  @return int
  @throws exIOError