Symfony sfUser setFlash function

/**
   * Sets a flash variable that will be passed to the very next action.
   *
   * @param  string $name     The name of the flash variable
   * @param  string $value    The value of the flash variable
   * @param  bool   $persist  true if the flash have to persist for the following request (true by default)
   */

# execute action
$this->getUser()->setFlash('msg', 'Hello world', false);
$this->forward('otherModule', 'otherAction');
# otherActionSuccess.php
echo $sf_user->getFlash('msg');# will be printed Hello world

# execute action
$this->getUser()->setFlash('msg', 'Hello world', false);
$this->redirect('otherModule', 'otherAction');
# otherActionSuccess.php
echo $sf_user->getFlash('msg');# will be printed empty (null)