src/Http/Request.php
protected function addHostHeader(UriInterface $uri)
    {
        $host = $uri->getHost();
        if ($port = $uri->getPort()) {
            $host = sprintf('%s:%s', $host, $port);
        }

        $this->headers['host'] = array($host);
    }
protected function addHostHeader(UriInterface $uri)
    {
        $host = $uri->getHost();
        if ($port = $uri->getPort()) {
            $host = sprintf('%s:%s', $host, $port);
        }

        $this->headers['host'] = array($host);
    }
Build host.

@param UriInterface $uri