code: func getByteSlice(size int) []byte {
  	fromPool := bsPool.Get()
  	if fromPool == nil {
  		return make([]byte, size)
  	}
  	bs := fromPool.([]byte)
  	if cap(bs) < size {
  		bs = make([]byte, size)
  	}
  	return bs[0:size]
  }
docs: // getByteSlice returns []byte with len == size.