Webscraping Symfony/Panther: Can't get HTML

$client = Client::createChromeClient();
$crawler = $client->request('GET', 'http://example.com');

/**
* Get all Html code of page
*/

$client->getCrawler()->html();

/**
* For example to filter field by ID = AuthenticationBlock and get text
*/

$loginUsername = $client->getCrawler()->filter('#AuthenticationBlock')->text();

$client = Client::createChromeClient();
$client->request('GET', 'http://example.com');

$html = $client->getInternalResponse()->getContent();
$crawler = new Symfony\Component\DomCrawler\Crawler($html);

// you can use following to get the whole HTML
$crawler->outerHtml();

// or specific parts
$crawler->filter('.some-class')->outerHtml();