code: private function loadChunk()
      {
          $portion = $this->pdGetDataChunk($this->api, $this->options, $this->reverse);
  
          $this->options = $portion['params'];
          $this->nextPageParams = $portion['nextParams'];
          $this->prevPageParams = $portion['prevParams'];
  
          if ($portion['data']) {
              $this->container = array_merge($this->container, $portion['data']);
          }
  
          if (!count($portion['params'])) {
              $this->fullyLoaded = true;
          }
      }
docs: Load elements chunk from server