title: Bind two UIview fram/Position using Rxswift
body: <p>I want to change <strong>view2</strong> position automatically when <strong>view1</strong> position will change and bind the both view position using Rxswift.</p>
  
  <p>I try to observe view frame/position using this</p>
  
  <pre><code>view.rx.observe(CGRect.self,"frame")
          .subscribe(onNext: {
              print($0 ?? (0,0))
          })
  </code></pre>
  
  <p>it <strong>print frame on init time</strong> but when change view position using constraints</p>
  
  <pre><code>self.constraintHorizontalCenterView.constant = 1000
  </code></pre>
  
  <p>it print nothing means this code not observe view position...</p>
  
  <p>Is there any way to observe continuously view position or bind view position?</p>