title: UnsafeMutablePointer<Void> to Concrete Object Type
body: <p>How can I cast from <code>UnsafeMutablePointer&lt;Void&gt;</code> to Concrete Object Type</p>
  
  <p>I've created a KVO observer and passed a custom class as context just like this</p>
  
  <pre><code>class Info : NSObject
  {
  }
  
  class Foo : NSObject {
      dynamic var property = ""
  }
  
  
  var info = Info()
  
  class Observing : NSObject {
      func observe1(object: NSObject) {
  
          object.addObserver(self, forKeyPath: "property", options: .New, context: &amp;info)
      }
  
      override func observeValueForKeyPath(keyPath: String, ofObject object: AnyObject, change: [NSObject : AnyObject], context: UnsafeMutablePointer&lt;Void&gt;) {
  
          println("observed \(keyPath) change:'\(change)' context: \(context)")
      }
  }
  
  let o = Observing()
  var object = Foo()
  o.observe1(object)
  object.property = "new value"
  </code></pre>
  
  <p>I would like to know how to cast context back to Info class</p>