return &pr, nil
}

type nopReadCloser struct {
	fn func()
}

func (n2 *nopReadCloser) Read(p []byte) (n int, err error) {
	panic("should not be called")
}

func (n2 *nopReadCloser) Close() error {
	if n2.fn != nil {
		n2.fn()
	}
	n2.fn = nil
	return nil

	bufLen := 32 * 1024
	b1, b2 := make([]byte, bufLen), make([]byte, bufLen)
	for i := 0; true; i++ {
		n1, e1 := io.ReadFull(r1, b1)
		n2, e2 := io.ReadFull(r2, b2)
		if n1 != n2 {
			return false, fmt.Sprintf("Read %d != %d bytes from the readers", n1, n2)
		}
		if !bytes.Equal(b1[:n1], b2[:n2]) {
			return false, fmt.Sprintf("After reading %d equal buffers (32Kib each), we got the following two strings:\n%v\n%v\n",
				i, b1, b2)
		}

		Peak:    peak,
		Curr:    curr,
		measure: rx.measure,
		N:       rx.N + o.N,
	}
}

func calcAvg(x, y float64, n1, n2 int64) float64 {
	if n1+n2 == 0 {
		return 0
	}
	avg := (x*float64(n1) + y*float64(n2)) / float64(n1+n2)
	return avg
}

// Add a new transfer
func (rx *XferStats) addSize(sz int64, t time.Duration) {
	if rx.measure == nil {