code: function through(transform, flush, objectMode) {
    const stream = new TransformStream({objectMode})
    stream._transform = transform || pass
    if (flush) stream._flush = flush
    return stream
  }
docs: Quickly create a object-mode duplex stream
  @param {function?} transform(chunk, encoding, done)
  @param {function?} flush(done)
  @param {boolean} objectMode
  @return {DuplexStream}