/** Optional, used for header-rewriting. See \ref afh_get_header(). */
void (*get_header)(void *map, size_t mapsize, char **buf, size_t *len);
/**
/** Optional, used for header-rewriting. See \ref afh_get_header(). */
void (*get_header)(void *map, size_t mapsize, char **buf, size_t *len);
/**