src/main/java/io/reactivex/Observable.java
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Observable<Observable<T>> window(long count, long skip, int bufferSize) {
        ObjectHelper.verifyPositive(count, "count");
        ObjectHelper.verifyPositive(skip, "skip");
        ObjectHelper.verifyPositive(bufferSize, "bufferSize");
        return RxJavaPlugins.onAssembly(new ObservableWindow<T>(this, count, skip, bufferSize));
    }
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Observable<Observable<T>> window(long count, long skip, int bufferSize) {
        ObjectHelper.verifyPositive(count, "count");
        ObjectHelper.verifyPositive(skip, "skip");
        ObjectHelper.verifyPositive(bufferSize, "bufferSize");
        return RxJavaPlugins.onAssembly(new ObservableWindow<T>(this, count, skip, bufferSize));
    }
@ CheckReturnValue @ SchedulerSupport ( SchedulerSupport . NONE ) public final Observable < Observable < T > > window ( long count , long skip , int bufferSize ) { ObjectHelper . verifyPositive ( count , "count" ) ; ObjectHelper . verifyPositive ( skip , "skip" ) ; ObjectHelper . verifyPositive ( bufferSize , "bufferSize" ) ; return RxJavaPlugins . onAssembly ( new ObservableWindow < T > ( this , count , skip , bufferSize ) ) ; }
Returns an Observable that emits windows of items it collects from the source ObservableSource. The resulting
ObservableSource emits windows every {@code skip} items, each containing no more than {@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="365" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/window4.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
@param skip
how many items need to be skipped before starting a new window. Note that if {@code skip} and
{@code count} are equal this is the same operation as {@link #window(long)}.
@param bufferSize
the capacity hint for the buffer in the inner windows
@return an Observable that emits windows every {@code skip} items containing at most {@code count} items
from the source ObservableSource
@throws IllegalArgumentException if either count or skip 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 windows every { @code skip } items each containing no more than { @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 = 365 src = https : // raw . github . com / wiki / ReactiveX / RxJava / images / rx - operators / window4 . 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 >