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 {
		var r io.Reader = w.pr
		if w.opts.MaximumFileSize > 0 {
			r = io.LimitReader(w.pr, w.opts.MaximumFileSize)
		}
		if _, err := io.Copy(w.f, r); err != nil {

By default it will listen on the IP address `127.0.0.1`, which is the IP for your machine to communicate with itself alone (`localhost`).

## `fastapi run`

When you run `fastapi run`, it will run on production mode by default.

It will have **auto-reload disabled** by default.