title: pass a flash message along with a gsp g:link
body: <p>In a grails3 create view, I'd like to have the <strong>Cancel button</strong> which just points back to the index page. On the index page, I'd like to display a message informing about the cancellation.     </p>
  
  <pre><code>&lt;g:link controller="${controllerName}" action="index" class="btn btn-default" params="[flash.message: 'Create cancelled']"&gt;
      Cancel
  &lt;/g:link&gt;
  </code></pre>
  
  <p>The above button is just a non-working mockup, no message is popping up. What would be the best way to achieve a <code>flash.message</code> popping up on the next page? </p>