src/main/java/io/reactivex/Completable.java
@SchedulerSupport(SchedulerSupport.NONE)
    public final void blockingAwait() {
        BlockingMultiObserver<Void> observer = new BlockingMultiObserver<Void>();
        subscribe(observer);
        observer.blockingGet();
    }
@SchedulerSupport(SchedulerSupport.NONE)
    public final void blockingAwait() {
        BlockingMultiObserver<Void> observer = new BlockingMultiObserver<Void>();
        subscribe(observer);
        observer.blockingGet();
    }
Subscribes to and awaits the termination of this Completable instance in a blocking manner and
rethrows any exception emitted.
<p>
<img width="640" height="432" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.blockingAwait.png" alt="">
<dl>
<dt><b>Scheduler:</b></dt>
<dd>{@code blockingAwait} 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>
@throws RuntimeException wrapping an InterruptedException if the current thread is interrupted