So I'm trying to make a mutation, and that should generate a txt file and send back to the user. So far I have this ```ts import { z } from "zod"; import fs from "fs"; import { router, publicProcedure } from "../trpc"; export const fileRouter = router({ get: publicProcedure .input(z.object({ navn: z.string(), email: z.string().email() })) .mutation(({ input }) => { const file = fs.writeFileSync("name.txt", input.navn + " " + input.email); return { file, }; }), }); ```