title: Theres is a way to be notified in swift if an UIImageView image has been set?
body: <p>if UIImageView were my class I would have solved this by doing:</p>
  
  <pre><code>class myUIImageView{
    var image : UIImage? {
     didSet {
      if self.image != nil{
        //do my stuff
      }
     }
    }
  
    //Other fields and functions
  }
  </code></pre>
  
  <blockquote>
    <p>What I want is to be notified (<em>Observer Like</em>)</p>
  </blockquote>