let worker = new Worker(module {
  onmessage = function ({ data }) {
    let mod = import(data);
    postMessage(mod.fn());
  };
}, { type: "module" });

let worker = new Worker(
  module {
    onmessage = function ({ data }) {
      let mod = import(data);
      postMessage(mod.fn());
    };
  },
  { type: "module", foo: "bar" },
);

worker.postMessage(module {
  export function fn() {
    return "hello!";
  }
});