code: function size($queue = null)
      {
          $count = 0;
  
          try {
              $count = $this->client->llen($this->_normalizeQueueName($queue));
          } catch (\Exception $e) {
              throw new exReadError('Error While Reading From Redis Client.', $e->getCode(), $e);
          }
  
          return $count;
      }
docs: Get Queue Size
  
  @param string $queue
  
  @return int
  @throws exIOError