size_t memory_used () const;
int avio_read (uint8_t* buffer, int const amount);
int64_t avio_seek (int64_t const pos, int whence);
private:
size_t memory_used () const;
int avio_read (uint8_t* buffer, int const amount);
int64_t avio_seek (int64_t const pos, int whence);
private: