title: RxSwift convert Observable<Bool> to Observable<Void>
body: <p>I am not so convinced with RxSwift yet, and it's really hard to cleat understanding. After reviewing different materials, I cant' still work and manipulate sequences.
  On the whole I have problem with type converting:</p>
  
  <pre><code>Cannot convert return expression of type 'Observable&lt;Bool&gt;' to return type 'Observable&lt;Void&gt;' (aka 'Observable&lt;()&gt;')    
  </code></pre>
  
  <p>I have CocoaAction processing, and should return <code>Observable&lt;Void&gt;</code></p>
  
  <pre><code>func stopProject() -&gt; CocoaAction {
      return CocoaAction { _ in
          let stopProject = stop(project: self.projectId)
          return stopProject.asObservable() //wrong converting
      }
  }
  </code></pre>
  
  <p>The <code>stop</code> function return <code>Observable&lt;Bool&gt;</code></p>
  
  <p><strong>Finish view:</strong></p>
  
  <pre><code>    return stop(project: self.projectId).flatMap { _ in
          Observable&lt;Void&gt;.empty()
      }
  </code></pre>