code: func generateRandomData(datasize int) ([]byte, error) {
  	b := make([]byte, datasize)
  	c, err := crand.Read(b)
  	if err != nil {
  		return nil, err
  	} else if c != datasize {
  		return nil, errors.New("short read")
  	}
  	return b, nil
  }
docs: // generates random data in heap buffer