title: New versioning NSNotificationCenter in reactive swift
body: <p>I would like to know below lines of code I mentioned NSNotificationCenter in swift 3.0 can be converted into RxSwif/RxCocoa</p>
  
  <pre><code>let imageDataDict:[String: UIImage] = ["image": image]
  
  // Post a notification
  NSNotificationCenter.defaultCenter().postNotificationName(notificationName, object: nil, userInfo: imageDataDict)
  
  // Register to receive notification in your class
  NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(self.showSpinningWheel(_:)), name: notificationName, object: nil)
  
  // handle notification
  func showSpinningWheel(notification: NSNotification) {
  if let image = notification.userInfo?["image"] as? UIImage {
  // do something with your image   
  }
  }
  </code></pre>