title: RxJava Delay the response conditionally
body: <p>I would like to delay the response at maximum for 500milliseconds.
  If updateData has taken say 400 milliseconds then I would like to delay for 100 milliseconds.</p>
  
  <p>With below code always I am delaying 500milliseconds.
  At the moment If backend taking 600 milliseconds then the total delay is 1100 milliseconds but I would like not to delay if it's over 500 milliseconds.</p>
  
  <pre><code>compositeDisposable.add(someRepo.updateData(dataRequest)
  .observeOn(schedulerProvider.mainThread())
  .delay(500, TimeUnit.MILLISECONDS)
  .subscribeWith(dataUpdateObserver())
  </code></pre>