Sending Strings as Files with CakePHP server response

From time to time you need to send string over response as file e.g. confiiuration files or calendar invites as follows bellow:

public function sendIcs()
{
  $icsString = $this->Calendars->generateIcs();
  $response = $this->response;

  // Inject string content into response body
  $response = $response->withStringBody($icsString);

  $response = $response->withType('ics');

  // Optionally force file download
  $response = $response->withDownload('filename_for_download.ics');

  // Return response object to prevent controller from trying to render
  // a view.
  return $response;
}

Example above is from official CakePHP book.