if err != nil && !testCase.errExpected || err == nil && testCase.errExpected {
			t.Errorf("expected error with invalid range: %v", err)
		}
		if h != testCase.spec {
			t.Errorf("Case %d: translated to incorrect header: %s expected: %s",
				i, h, testCase.spec)
		}
	}

	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 {
			msg := fmt.Sprintf("unable to write to log file %v: %v", w.f.Name(), err)

		contentType := r.Header.Get("Content-Type")
		if contentType == "application/json" {
			w.Header().Set("Content-Type", "application/json")
			jsonEncoder := json.NewEncoder(w)
			jsonEncoder.Encode(metrics)
			return
		}

		// If not JSON, return plain text. We format it as a markdown table for
		// readability.
		w.Header().Set("Content-Type", "text/plain")
		var b strings.Builder

		return 0, 0, err
	}

	start = h.Start
	if h.IsSuffixLength {
		start = resourceSize + h.Start
		if start < 0 {
			start = 0
		}
	}
	return start, length, nil
}

// Parse a HTTP range header value into a HTTPRangeSpec
func parseRequestRangeSpec(rangeString string) (hrange *HTTPRangeSpec, err error) {
	// Return error if given range string doesn't start with byte range prefix.

	fmt.Fprintln(banner, color.Blue("Version:")+color.Bold(" %s (%s %s/%s)", ReleaseTag, runtime.Version(), runtime.GOOS, runtime.GOARCH))
}

func versionBanner(c *cli.Context) io.Reader {
	banner := &strings.Builder{}
	fmt.Fprintln(banner, color.Bold("%s version %s (commit-id=%s)", c.App.Name, c.App.Version, CommitID))