Set the host of the request. Including a port in the host will modify the port of the request.
string $host Host to set (e.g. www.yahoo.com, www.yahoo.com:80):
Overrides RequestInterface::setHost
public function setHost($host) {
$this->url
->setHost($host);
$this
->setPort($this->url
->getPort());
return $this;
}