title: In Swift, What is the difference between (()->()) and @escaping () -> Void?
body: <p>What is the difference between (()->()) and @escaping () -> Void?</p>
  
  <pre><code>func foo(_ completion: (() -&gt; ()) { }
  
  func boo(_ completion: @escaping () -&gt; Void) { }
  </code></pre>