How to aggregate user data from duplicate URLs

import { Router } from "crawlee";

export const router = Router.create();

// ... other handlers

// imagine the category handler is called twice
router.addHandler("CATEGORY", async ({ enqueueLinks }) => {
  // ... parsing

  // result of first call
  await enqueueLinks({
    urls: ["https://example.com/my-product"],
    userData: { category: "foo" },
    label: "DETAIL",
  });

  // result of second call
  await enqueueLinks({
    urls: ["https://example.com/my-product"],
    userData: { category: "bar" },
    label: "DETAIL",
  });
});

router.addHandler("DETAIL", async ({ request }) => {
  // todo: how to get both "foo" and "bar" here?
  const category = request.userData.category;

  // ... saving
});