title: RXKotlin how do you map to void?
body: <p>Sorry nooby kotlin question</p>
  
  <pre><code>func someThingElse(): Observable&lt;String&gt; {
     return Observable.just("aasd")
  } 
  
  fun doSomething(): Observable&lt;Void&gt; {
      return someThisElse().fetch().map { () } 
  }
  </code></pre>
  
  <p>How do i return an observable of void?
  I tried <code>void</code>, <code>Void()</code>, <code>Void</code></p>