title: Driver is not updation with latest value
body: <p><strong>I have one filter type enum</strong></p>
  
  <p>import RxSwift
  import RxCocoa</p>
  
  <pre><code>enum FilterType {
      case all
      case rental
      case purchased
  }
  
  var currentCategory: Driver&lt;FilterType&gt; = Driver.just(.all)
  </code></pre>
  
  <p><strong>whenever I am updating the currentCategory on segment click. like below</strong> 
  currentCategory = Driver.just(.purchased).</p>
  
  <p><strong>I am always getting the same value all every time. I am new to RXSwift and RXCocoa. Please help me to get out of this situation. Thanks in advance.</strong></p>