<?php
$formset = new FormSet();
$formset->addForm(
    $this->createForm('form_1', $foo),
    function($form) use ($commandBus) {
        $commandBus->execute($form->getData());
    }
);
$formset->addForm(
    $this->createForm('form_1', $bar),
    function() {
        echo 'form 2 complete, yay!';
    }
);
$formset->submitRequest(new Request());