TechEmpower.FrameworkBenchmarks/frameworks/PHP/zend1/application/controllers/PlaintextController.php

<?php

class PlaintextController extends Zend_Controller_Action
{
    public function indexAction()
    {
      $this->_helper->viewRenderer->setNoRender(true);
      $this->getResponse()
           ->setHeader('Content-Type', 'text/plain')
           ->appendBody('Hello, World!');
    }
}