const { Readable, Writable, Transform } = require('stream');

let inStream = Readable();
inStream._read = () => inStream.push('test');

let asyncTxStream = Transform({objectMode: true});
asyncTxStream._transform = (buff, enc, next) => {
  setTimeout(() => {
    console.log(buff.toString());
    asyncTxStream.push(buff);
    next();
  }, 20)
}

var txStream = Transform({objectMode: true});
txStream._transform = (buff, enc, next) => {
  console.log(buff.toString());
  txStream.push(buff);
  next();
}

let outStream = Writable({objectMode: true});
outStream._write = (chunk, enc, next) => next();


let stream = Readable({objectMode: true});
stream._read = () => stream.push(inStream.read());


// broken
stream
  .pipe(asyncTxStream)
  .pipe(outStream);

// works
// stream
//   .pipe(txStream)
//   .pipe(outStream);

// works
// inStream
//   .pipe(asyncTxStream)
//   .pipe(outStream);