Change default ordering of taxonomy terms – pre_get_terms

Now I am able to sort taxonomy terms by term_order using below snippets. But I am still seeking answer for the original question “How to do it using pre_get_terms”.

function foo_tax_order($orderby, $args){

        return 't.term_order';
}
add_filter('get_terms_orderby', 'foo_tax_order', 10, 2);