Redirect for subrouters

Commented here, but since the issue cannot be reopened, I opened this issue to continue the discussion.

Copy of my comment there:

I'm not sure whether my question relates to the initial question, but perhaps it makes sense when subrouters are used? Consider this:

复制

router.Route("/{username}", func(r chi.Router) {
	r.Get("/", func(w http.ResponseWriter, request *http.Request) {
		// r.Redirect("/details")  <---- This is where I want to redirect to, keeping the subrouter's prefix (/{username}).
	})

	r.Get("/details", func(writer http.ResponseWriter, request *http.Request) {
		// ...                     <---- Redirects here
	})
} 

Originally posted by @shamilovstas in #709