public function withXMLBody($data, SerializationContext $context = null)
    {
        if (is_string($data)) {
            $xml = $data;
        } else {
            $xml = SerializerBuilder::create()->build()->serialize($data, 'xml', $context);
        }
        $this->addHeader('Content-Type', 'text/xml; charset=utf-8');
        $this->withBody($xml);

        return $this;
    }