io.SeekStart

```
type nopReadCloser struct {
	r *bytes.Reader
}

func (r *nopReadCloser) Read(p []byte) (int, error) {
	n, err := r.r.Read(p)
	if err == io.EOF {
		r.r.Seek(0, io.SeekStart)
	}
	return n, err
}
```

why this function call `r.r.Seek(0, io.SeekStart)`, this. may call loop infinite