code: func NewHandler(manifest string) Handler {
  	mux := http.NewServeMux()
  
  	mux.HandleFunc(activatePath, func(w http.ResponseWriter, r *http.Request) {
  		w.Header().Set("Content-Type", DefaultContentTypeV1_1)
  		fmt.Fprintln(w, manifest)
  	})
  
  	return Handler{mux: mux}
  }
docs: // NewHandler creates a new Handler with an http mux.