Function broadcast

benchmark/worker/echo.js:49–61

()

  }

  function broadcast() {
    if (broadcasts++ === n) {
      bench.end(n);
      for (const worker of workerObjs) {
        worker.unref();
      }
      return;
    }
    for (const worker of workerObjs) {
      for (let i = 0; i < sends; ++i)
        worker.postMessage(payload);
    }
  }

  function onMessage() {
    if (++msgCount === expectedPerBroadcast) {