code: func sockjsHandlerWithRequest(
  	prefix string,
  	opts sockjs.Options,
  	handleFunc func(sockjs.Session, *http.Request),
  ) http.Handler {
  	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
  		sockjs.NewHandler(prefix, opts, func(session sockjs.Session) {
  			handleFunc(session, r)
  		}).ServeHTTP(w, r)
  	})
  }
docs: // sockjsHandlerWithRequest is a wrapper around the sockjs.Handler that
  // includes a *http.Request context.