code: func (r *SystemBootOptionsResponse) UnmarshalBinary(buf []byte) error {
  	if len(buf) < 3 {
  		return ErrShortPacket
  	}
  	r.CompletionCode = CompletionCode(buf[0])
  	r.Version = buf[1]
  	r.Param = buf[2]
  	r.Data = buf[3:]
  	return nil
  }
docs: // UnmarshalBinary implementation to handle variable length Data