size_t used_of_buffered_data = 0; // How many bytes of the first element of <buffered_data> that is already used. Protected by <mutex>.
size_t seen_keyframe = false;
};
size_t used_of_buffered_data = 0; // How many bytes of the first element of <buffered_data> that is already used. Protected by <mutex>.
size_t seen_keyframe = false;
};