<!DOCTYPE html>
<html class="test-wait">
<script id="workerScript" type="text/worker">
  // Blob will pass a huge Uint8Array object whose stringification will take long
  const encoder = new TextEncoderStream()
  const blob = new Blob([new ArrayBuffer(1338720)])
  const writable = new WritableStream()
  blob.stream().pipeThrough(encoder).pipeTo(writable)
  // Wait a bit for the piping to start
  Promise.resolve().then(() => postMessage('started'));
</script>
<script>
  const worker = new Worker(URL.createObjectURL(new Blob([
    document.getElementById("workerScript").textContent
  ])))
  worker.onmessage = () => {
    worker.terminate();
    document.documentElement.classList.remove("test-wait");
  };
</script>
