/**
  * {@inheritdoc}
  */
 public function serialize($keys = array(), $valueSeparator = '=', $fieldSeparator = ' ', $quote = '"')
 {
     $pluginInfo = $this->pluginList->getNext($this->subjectType, 'serialize');
     if (!$pluginInfo) {
         return parent::serialize($keys, $valueSeparator, $fieldSeparator, $quote);
     } else {
         return $this->___callPlugins('serialize', func_get_args(), $pluginInfo);
     }
 }