xfarray_load_next
error = xfarray_load_next(ra->free_records, &ra->array_cur,
error = xfarray_load_next(si->array, &idx, recp);
int xfarray_load_next(struct xfarray *array, xfarray_idx_t *idx, void *rec);
int ret = xfarray_load_next(array, idx, rec);