Request::__construct

public function __construct(string $method, UriInterface $uri, array $headers = null, StreamInterface $body = null, string $version = null)
{
	parent::__construct($headers, $body, $version);

	$this->method = $method;
	$this->uri = $uri;

	// PSR-7: During construction, implementations MUST attempt to set the Host header from a provided URI if no Host header is provided.
	if ($uri->getHost() != '' && !$this->hasHeader('Host'))
	{
		$this->headers->set('Host', $uri->getHost());
	}
}