title: Updating Struct instance
body: <p>I'm Use structures by default when possible,
  what's the best practice to update the original struct instance a copy of it was passed to another variable.
  let's say I have a <code>Post</code> struct</p>
  
  <pre class="lang-swift prettyprint-override"><code>struct Post {
      let title: String
      let likes: Int
      let viewsCount:Int
      var comments:[Comment]
  }
  </code></pre>
  
  <p>and we have a simple Master-Details Screens 
  when pushing the details screen we are copying the <code>post</code> to the details scene, and there the data may be changed as likes increments, added comments and so on,
  so when pop This ViewController, to the new data model to update the original model in the Master ViewController.
  what are the possible solution and the best practices for it?
  assuming we are using MVC or MVP</p>