title: What different between Proxy and Delegate in iOS design mode
body: <p>What different between Proxy and Delegate in iOS design?
  I am reading project there I have not seen the design patterns, A small number of Proxy, else is Delegate.</p>
  
  <p>Any difference between them?</p>
  
  <pre><code>@protocol BaseViewControllerProxy &lt;NSObject&gt; 
  
  @optional
  
  - (void)updateLayout:(CGRect)rect;
  - (void)viewWillAppear:(BOOL)animated;  @optional
  
  - (void)viewWillTransitionToSize;
  - (void)viewWillAnimateTransitionToSize;
  - (void)viewDidTransitionToSize;
  - (void)viewWillTransitionFrom:(UITraitCollection *)oldCollection toTraitCollection:(UITraitCollection *)newCollection;
  - (void)viewWillAnimateTransitionToTraitCollection:(UITraitCollection *)newCollection;
  - (void)viewDidTransitionToTraitCollection:(UITraitCollection *)newCollection;
  
  @end
  </code></pre>