src/main/java/io/reactivex/Observable.java
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Iterable<T> blockingIterable(int bufferSize) {
        ObjectHelper.verifyPositive(bufferSize, "bufferSize");
        return new BlockingObservableIterable<T>(this, bufferSize);
    }
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Iterable<T> blockingIterable(int bufferSize) {
        ObjectHelper.verifyPositive(bufferSize, "bufferSize");
        return new BlockingObservableIterable<T>(this, bufferSize);
    }
Converts this {@code Observable} into an {@link Iterable}.
<p>
<img width="640" height="315" src="https://github.com/ReactiveX/RxJava/wiki/images/rx-operators/blockingIterable.o.png" alt="">
<dl>
<dt><b>Scheduler:</b></dt>
<dd>{@code blockingIterable} does not operate by default on a particular {@link Scheduler}.</dd>
</dl>

@param bufferSize the number of items to prefetch from the current Observable
@return an {@link Iterable} version of this {@code Observable}
@see <a href="http://reactivex.io/documentation/operators/to.html">ReactiveX documentation: To</a>