Demo desired ability in Apollo Router Rhai plugin

main.rhai

fn process_response(response) {
  response.headers["set-cookie"] = "foo=bar; Domain=localhost; Path=/; Expires=Wed, 04 Jan 2023 17:25:27 GMT; HttpOnly; Secure; SameSite=None";
  // This overwrites the first header set above
  response.headers["set-cookie"] = "foo2=bar2; Domain=localhost; Path=/; Expires=Wed, 04 Jan 2023 17:25:27 GMT; HttpOnly; Secure; SameSite=None";

  // This does not work
  response.headers["set-cookie"] = [
    "foo=bar; Domain=localhost; Path=/; Expires=Wed, 04 Jan 2023 17:25:27 GMT; HttpOnly; Secure; SameSite=None",
    "foo2=bar2; Domain=localhost; Path=/; Expires=Wed, 04 Jan 2023 17:25:27 GMT; HttpOnly; Secure; SameSite=None",
  ];
}

fn supergraph_service(service) {
  const response_callback = Fn("process_response");
  service.map_response(response_callback);
}