code: func (wpr *Wrapper) Read(p []byte) (n int, err error) {
  	n, err = wpr.ReadAt(p, 0)
  	wpr.L -= int64(n)
  	wpr.O += int64(n)
  	wpr.O %= wpr.N
  	return n, err
  }
docs: // Read reads from the current offset into p, wrapping at Cap()