code: func ReverseBytes(buf []byte) []byte {
  	var res []byte
  	if len(buf) == 0 {
  		return res
  	}
  
  	// Walk till mid-way, swapping bytes from each end:
  	// b[i] and b[len-i-1]
  	blen := len(buf)
  	res = make([]byte, blen)
  	mid := blen / 2
  	for left := 0; left <= mid; left++ {
  		right := blen - left - 1
  		res[left] = buf[right]
  		res[right] = buf[left]
  	}
  	return res
  }
docs: // ReverseBytes returns the buf in the opposite order