function slowStream(value, encoding) {
  const stream = new PassThrough()
  let index = 0

  tick()

  return stream

  function send() {
    if (index === value.length) {
      stream.end()
    } else {
      stream.write(value.slice(index, ++index), encoding || 'utf8', tick)
    }
  }

  function tick() {
    setTimeout(send, 4)
  }
}
@param {Uint8Array | string} value
  Value.
@param {BufferEncoding | undefined} [encoding]
  Encoding.
@returns {PassThrough}
  Stream.