gistfile1.php

<?php

$this->getUser()->setFlash('alert', array(
  'close' => true,
  'title' => '',
  'text' => '',
  'buttons' => array(
    array('class' => 'btw-primary', 'route' => '@mycq_collections', 'text' => 'View Collections'),
    array('route' => 'close', 'text' => 'No, thanks!')
  )
));

route => close is a special use case, which will create a button which will close the alert div.