And for example use, this is the way I use this feature :
```php
//setup soap server
$soapServer->setReturnResponse(true);
$soapServer->setObject($handler);
$response = $soapServer->handle();

//error management
if ($response instanceOf \SoapFault) {
    $this->logger->addWarning($soapServer->getException());
    $soapServer->getSoap()->fault($response->faultcode, $response->getMessage());
        return $this->nullResponse();
 }

 return new Response($response, 200, array('content-type' => 'text/xml'));
 ```