void (*audio_process)(void *cls, void *session, const void *buffer, int buflen);
void (*audio_flush)(void *cls, void *session);
void (*audio_destroy)(void *cls, void *session);
void (*audio_process)(void *cls, void *session, const void *buffer, int buflen);
void (*audio_flush)(void *cls, void *session);
void (*audio_destroy)(void *cls, void *session);