title: RxJava operator Debounce is not working
body: <p>I want to implement place autocomplete in Android application, and for this I'm using Retrofit and RxJava. I want to make response every 2 seconds after user type something. I'm trying to use debounce operator for this, but it's not working. It's giving me the result immediately without any pause.</p>
  
  <pre><code> mAutocompleteSearchApi.get(input, "(cities)", API_KEY)
              .debounce(2, TimeUnit.SECONDS)
              .subscribeOn(Schedulers.io())
              .observeOn(AndroidSchedulers.mainThread())
              .flatMap(prediction -&gt; Observable.fromIterable(prediction.getPredictions()))
              .subscribe(prediction -&gt; {
                  Log.e(TAG, "rxAutocomplete : " + prediction.getStructuredFormatting().getMainText());
              });
  </code></pre>