fXmlRpc\Serializer\SerializerInterface::serialize PHP Method

    public function serialize($method, array $params = []);

 /** {@inheritdoc} */
 public function call($methodName, array $params = [])
 {
     if (!is_string($methodName)) {
         throw InvalidArgumentException::expectedParameter(0, 'string', $methodName);
     }
     $params = array_merge($this->prependParams, $params, $this->appendParams);
     $payload = $this->serializer->serialize($methodName, $params);
     $response = $this->transport->send($this->uri, $payload);
     return $this->parser->parse($response);
 }