Host not set on request URI

[fredemmott]

<<__EntryPoint>>
async function site_main_async(): Awaitable<noreturn> {
   $request = Usox\HackTTP\createServerRequestFromGlobals();
   \var_dump($request->getUri()->getHost());
   exit(0);
}

$ curl -H "Host: docs.hhvm.com" http://localhost:8080
string(0) ""
$ curl http://localhost:8080
string(0) ""