title: How trigger a function inside component whenever arguments change in Emnber octane
body: <p>so i have a parent in controller like this</p>
  <pre><code>import Controller from '@ember/controller';
  
  export default class IndexController extends Controller {
  @service firebaseApp;
  @service fastboot;
  @tracked user =false;
  
  async init(){
   super.init(...arguments);
   if (!this.fastboot.isFastBoot){
    const auth =  await this.firebaseApp.auth();
    auth.onAuthStateChanged((user)=&gt;{
       if(user){
         this.user = true
       } else {
         this.user = false
       }
        })
       }
     }
  </code></pre>
  <p>then call a component loadData like this
  &lt;LoadData @user={{this.user}}/&gt;</p>
  <p>the question is how to execute a function inside component loadData when @user change?</p>