code: func (l binaryFreeList) Borrow() []byte {
  	var buf []byte
  	select {
  	case buf = <-l:
  	default:
  		buf = make([]byte, 8)
  	}
  	return buf[:8]
  }
docs: // Borrow returns a byte slice from the free list with a length of 8.  A new
  // buffer is allocated if there are not any available on the free list.