src/main/java/io/reactivex/Observable.java
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Observable<Observable<T>> window(long count) {
        return window(count, count, bufferSize());
    }
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Observable<Observable<T>> window(long count) {
        return window(count, count, bufferSize());
    }
@ CheckReturnValue @ SchedulerSupport ( SchedulerSupport . NONE ) public final Observable < Observable < T > > window ( long count ) { return window ( count , count , bufferSize ( ) ) ; }
Returns an Observable that emits windows of items it collects from the source ObservableSource. The resulting
ObservableSource emits connected, non-overlapping windows, each containing {@code count} items. When the source
ObservableSource completes or encounters an error, the resulting ObservableSource emits the current window and
propagates the notification from the source ObservableSource.
<p>
<img width="640" height="400" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/window3.png" alt="">
<dl>
<dt><b>Scheduler:</b></dt>
<dd>This version of {@code window} does not operate by default on a particular {@link Scheduler}.</dd>
</dl>

@param count
the maximum size of each window before it should be emitted
@return an Observable that emits connected, non-overlapping windows, each containing at most
{@code count} items from the source ObservableSource
@throws IllegalArgumentException if either count is non-positive
@see <a href="http://reactivex.io/documentation/operators/window.html">ReactiveX operators documentation: Window</a>
Returns an Observable that emits windows of items it collects from the source ObservableSource . The resulting ObservableSource emits connected non - overlapping windows each containing { @code count } items . When the source ObservableSource completes or encounters an error the resulting ObservableSource emits the current window and propagates the notification from the source ObservableSource . <p > <img width = 640 height = 400 src = https : // raw . github . com / wiki / ReactiveX / RxJava / images / rx - operators / window3 . png alt = > <dl > <dt > <b > Scheduler : < / b > < / dt > <dd > This version of { @code window } does not operate by default on a particular { @link Scheduler } . < / dd > < / dl >