Get full url of request in plugin

How do I get the absolute URL, including scheme and host in

func (plugin *MyPlugin) ServeHTTP(response http.ResponseWriter, request *http.Request)

I can see request.URL or request.RequestURI but these have only the path and not the host.
I can get the host from request.Host but there is no scheme.
request.URL.Scheme is empty, which makes sense as request.URL is only a path.

So how do I get my full URL?

Do those headers exist?

X-Forwarded-Port: 443
X-Forwarded-Proto: https
X-Forwarded-Server: s1

Yes X-Forwarded-Proto does. I’d actually just found it and implemented a get on it and then defaulted to https. It’s a bit of a muddle mess pulling bits from here there and everywhere to make the URL which I’d suggest should be full in Request.URL but it’s working now. Thanks very much for your reply.