once sync.Once
	done func()
}

// CloseWithError close with supplied error the writer end.
func (w *PipeWriter) CloseWithError(err error) error {
	err = w.PipeWriter.CloseWithError(err)
	w.once.Do(func() {
		w.done()
	})
	return err
}

// PipeReader is similar to io.PipeReader with wait group
type PipeReader struct {
	*io.PipeReader
	wait func()
}

// CloseWithError close with supplied error the reader end

			n, err := mw.Write(data[:])
			if err != nil {
				w.CloseWithError(err)
				return
			}
			if n != len(data) {
				w.CloseWithError(io.ErrShortWrite)
				return
			}
			for item := range m.opCh {
				err = item.EncodeMsg(mw)
				if err != nil {
					break
				}
			}
			mw.Flush()
			w.CloseWithError(err)
		}()
		return r
	}

	globalLocalDrivesMu.RLock()

	rb := ringbuffer.NewBuffer(buf[:cap(buf)]).SetBlocking(true)

	bw := &streamingBitrotWriter{
		iow:          ioutil.NewDeadlineWriter(rb.WriteCloser(), globalDriveConfig.GetMaxTimeout()),
		closeWithErr: rb.CloseWithError,
		h:            h,
		shardSize:    shardSize,
		canClose:     &sync.WaitGroup{},
		byteBuf:      buf,
	}
	bw.canClose.Add(1)
	go func() {
		defer bw.canClose.Done()

`TryRead` and `TryWrite` are still available for non-blocking reads and writes.

To signify the end of the stream, close the ring buffer from the writer side with `rb.CloseWriter()`

Either side can use `rb.CloseWithError(err error)` to signal an error and close the ring buffer. 
Any reads or writes will return the error on next call.

}

// Close closes the writer.
// Any accepted writes will be flushed. Any new writes will be rejected.
// Once Close() exits, files are synchronized to disk.
func (w *Writer) Close() error {
	w.pw.CloseWithError(nil)

	if w.f != nil {
		if err := w.closeCurrentFile(); err != nil {
			return err
		}
	}

	return nil
}

var stdErrEnc = json.NewEncoder(os.Stderr)

func (w *Writer) listen() {
	for {