public function count() {
    if (isset($this->_href)) {
      $headers = Recurly_Base::_head($this->_href, $this->_client);
      if (isset($headers['x-records'])) {
        return intval($headers['x-records']);
      }
    } elseif (isset($this->_objects) && is_array($this->_objects)) {
      return count($this->_objects);
    }

    return null;
  }