title: SwitchMap with delayed observable
body: <pre><code> Observable
       .interval(2, TimeUnit.SECONDS)
       .switchMap(integer -&gt; 
          Observable
                   .just(integer * 2) 
                   .delay(5,SECONDS))
       .subscribe(integer -&gt; { System.out.println(integer);});
  </code></pre>
  
  <p>As I understood, after switch map we should subscribe to last created observable, so I expect output "8" after 20 seconds, but it waits forever</p>