code: func (b *bstream) MarshalBinary() ([]byte, error) {
  	buf := new(bytes.Buffer)
  	err := binary.Write(buf, binary.BigEndian, b.count)
  	if err != nil {
  		return nil, err
  	}
  	err = binary.Write(buf, binary.BigEndian, b.stream)
  	if err != nil {
  		return nil, err
  	}
  	return buf.Bytes(), nil
  }
docs: // MarshalBinary implements the encoding.BinaryMarshaler interface