src/main/java/io/reactivex/Observable.java
@SchedulerSupport(SchedulerSupport.NONE)
    public final void blockingForEach(Consumer<? super T> onNext) {
        Iterator<T> it = blockingIterable().iterator();
        while (it.hasNext()) {
            try {
                onNext.accept(it.next());
            } catch (Throwable e) {
                Exceptions.throwIfFatal(e);
                ((Disposable)it).dispose();
                throw ExceptionHelper.wrapOrThrow(e);
            }
        }
    }
@SchedulerSupport(SchedulerSupport.NONE)
    public final void blockingForEach(Consumer<? super T> onNext) {
        Iterator<T> it = blockingIterable().iterator();
        while (it.hasNext()) {
            try {
                onNext.accept(it.next());
            } catch (Throwable e) {
                Exceptions.throwIfFatal(e);
                ((Disposable)it).dispose();
                throw ExceptionHelper.wrapOrThrow(e);
            }
        }
    }
Consumes the upstream {@code Observable} in a blocking fashion and invokes the given
{@code Consumer} with each upstream item on the <em>current thread</em> until the
upstream terminates.
<p>
<img width="640" height="330" src="https://github.com/ReactiveX/RxJava/wiki/images/rx-operators/blockingForEach.o.png" alt="">
<p>
<em>Note:</em> the method will only return if the upstream terminates or the current
thread is interrupted.
<p>
This method executes the {@code Consumer} on the current thread while
{@link #subscribe(Consumer)} executes the consumer on the original caller thread of the
sequence.
<dl>
<dt><b>Scheduler:</b></dt>
<dd>{@code blockingForEach} does not operate by default on a particular {@link Scheduler}.</dd>
<dt><b>Error handling:</b></dt>
<dd>If the source signals an error, the operator wraps a checked {@link Exception}
into {@link RuntimeException} and throws that. Otherwise, {@code RuntimeException}s and
{@link Error}s are rethrown as they are.</dd>
</dl>

@param onNext
the {@link Consumer} to invoke for each item emitted by the {@code Observable}
@throws RuntimeException
if an error occurs
@see <a href="http://reactivex.io/documentation/operators/subscribe.html">ReactiveX documentation: Subscribe</a>
@see #subscribe(Consumer)