vibed: how to use pure HTML instead of template engine?

[Suliman via Digitalmars-d-learn]

shared static this()
{
	auto router = new URLRouter;
	router.get("/", &root);

	auto settings = new HTTPServerSettings;
     settings.port = 8080;
     listenHTTP(settings, router);
}


void root(HTTPServerRequest req, HTTPServerResponse res)
{
	serveStaticFiles("public/");
}


1. Do I need write "./public/" ? In examples often simply 
"public/"
2. What incoming parameters ("HTTPServerRequest req, 
HTTPServerResponse res") mean? Why I should to specify them?
3. Why code with: "res.writeBody("Hello, World!", "text/plain");"
and "router.get("*", serveStaticFiles("./public/"));" also work, 
but my variant (see code above) do not load say that page not 
found?
4. How to specify page that I need to load, why in examples there 
is only link to folder like public? But what if I want to load 
public/foo.html?