title: How can I use a $broadcast start / stop event to toggle a field between true and false?
body: <p>I have two events:</p>
  
  <pre><code>$rootScope.$broadcast('cfpLoadingBar:started');
  $rootScope.$broadcast('cfpLoadingBar:completed');
  </code></pre>
  
  <p>How can I "in my controller" use these events to toggle on and off the state of a property called "loading" ?</p>