title: How to replace a simple delegate protocol with RxSwift?
body: <p>I'm looking for the optimal way to avoid defining </p>
  
  <pre><code>protocol SomeTableviewCellDelegate: class {
      func didSelectTopic(topic: RTopic)
  }
  </code></pre>
  
  <p>and use RxSwift instead.</p>
  
  <p>I already have defined</p>
  
  <pre><code>var didSelectTopic: Observable&lt;RTopic&gt; {
      return _didSelectTopic.asObservable()
  }
  private let _didSelectTopic = PublishSubject&lt;RTopic&gt;()
  
  var didDeselectTopic: Observable&lt;RTopic&gt; {
       return _didDeselectTopic.asObservable()
  }
  private let _didDeselectTopic = PublishSubject&lt;RTopic&gt;()
  </code></pre>
  
  <p>I can't find the proper way to emit a topic (I am new to RxSwift).</p>