Neos\Flow\Http\Client\Browser::submit PHP Method

    public function submit(Form $form)
    {
        return $this->request($form->getUri(), $form->getMethod(), $form->getPhpValues(), $form->getPhpFiles());
    }

 /**
  * Go to the previous form page
  *
  * @param \Symfony\Component\DomCrawler\Form $form
  * @return \Neos\Flow\Http\Response
  */
 protected function gotoPreviousFormPage(\Symfony\Component\DomCrawler\Form $form)
 {
     $previousButton = $this->browser->getCrawler()->filterXPath('//nav[@class="form-navigation"]/*/*[contains(@class, "previous")]/button');
     $previousButton->rewind();
     $form->set(new InputFormField($previousButton->current()));
     return $this->browser->submit($form);
 }