Methods for storing integer bytes

    void AppendBool(bool data)
    {
      message_.append ( reinterpret_cast<char*>(&data), sizeof(data) );
    }

    void Append16(int16_t data)
    {
      message_.append ( reinterpret_cast<char*>(&data), sizeof(data) );
    }

    void Append32(int32_t data)
    {
      message_.append ( reinterpret_cast<char*>(&data), sizeof(data) );
    }

    void Append64(int64_t data)
    {
      message_.append ( reinterpret_cast<char*>(&data), sizeof(data) );
    }

    void AppendString(const char* data, size_t length)
    {
      message_.append ( data, length );
    }