title: await with a TestScheduler
body: <p>I am using the TestScheduler to test and design my sequences however for a snippet like below the TestScheduler hangs while the DefaultScheduler works fine. It may possible to remove await in certain cases but this is not what I want for the obvious reasons. So is there a way to use the TestScheduler and await together?</p>
  
  <pre><code>var testScheduler = new TestScheduler();
  var response = await Observable.Return(Unit.Default).Delay(TimeSpan.FromTicks(1000),testScheduler);
  testScheduler.AdvanceBy(1000);
  response.ShouldNotBeNull();
  </code></pre>