<!DOCTYPE html>
<meta charset="utf-8">
<script>
  // This can't be in WPT because of bug 1766711.
  let a = new AbortController()
  a.abort()
  let b = new File(['ó ¬a'], 'a', {})
  let c = new WritableStream()
  b.stream().tee()[0].pipeTo(c, { 'signal': a.signal })
</script>
