How to set up custom response headers at procedure level

getPoolByPoolId: publicProcedure.query(async ({ ctx }) => {
    const pool = await ctx.raydiumClient.fetchJupTokenList(
      JupTokenType.Strict,
      true,
    );
    // ctx.headers["Cache-Controlz"] = "public, max-age=600";
    if ("headers" in ctx) {
      ctx.headers.append("x-test-Control", "public, max-age=600");
      console.log("ctx.headers", ctx.headers);
    }
    return pool;
  }),