code: public function serialize()
      {
          $this->requestAllPages();
          return serialize(
              array(
                  'page' => $this->page,
                  'key' => $this->key,
                  'data' => $this->data
              )
          );
      }
docs: String representation of CanvasArray
  
  @return string
  
  @see http://php.net/manual/en/serializable.serialize.php
  Serializable::serialize()