Submit handler #2 for the chained form.
function batch_test_chained_form_submit_2($form, &$form_state) {
batch_test_stack('submit handler 2');
batch_test_stack('value = ' . $form_state['values']['value']);
$form_state['values']['value']++;
batch_set(_batch_test_batch_2());
// This redirect should not be taken into account.
$form_state['redirect'] = 'should/be/discarded';
}