title: How to unsubscribe from Observable in RxSwift?
body: <p>I want to unsubscribe from Observable in RxSwift. In order to do this I used to set Disposable to nil. But it seems to me that after updating to RxSwift 3.0.0-beta.2 this trick does not work and I can not unsubscribe from Observable:</p>
  
  <pre><code>//This is what I used to do when I wanted to unsubscribe
  var cancellableDisposeBag: DisposeBag?
  
  func setDisposable(){
      cancellableDisposeBag = DisposeBag()
  }
  
  func cancelDisposable(){
      cancellableDisposeBag = nil
  }
  </code></pre>
  
  <p>So may be somebody can help me how to unsubscribe from Observable correctly?</p>