src/main/java/io/reactivex/Observable.java
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public final <U> Observable<T> skipUntil(ObservableSource<U> other) {
        ObjectHelper.requireNonNull(other, "other is null");
        return RxJavaPlugins.onAssembly(new ObservableSkipUntil<T, U>(this, other));
    }
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public final <U> Observable<T> skipUntil(ObservableSource<U> other) {
        ObjectHelper.requireNonNull(other, "other is null");
        return RxJavaPlugins.onAssembly(new ObservableSkipUntil<T, U>(this, other));
    }
Returns an Observable that skips items emitted by the source ObservableSource until a second ObservableSource emits
an item.
<p>
<img width="640" height="375" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/skipUntil.png" alt="">
<dl>
<dt><b>Scheduler:</b></dt>
<dd>{@code skipUntil} does not operate by default on a particular {@link Scheduler}.</dd>
</dl>

@param <U> the element type of the other ObservableSource
@param other
the second ObservableSource that has to emit an item before the source ObservableSource's elements begin
to be mirrored by the resulting ObservableSource
@return an Observable that skips items from the source ObservableSource until the second ObservableSource emits an
item, then emits the remaining items
@see <a href="http://reactivex.io/documentation/operators/skipuntil.html">ReactiveX operators documentation: SkipUntil</a>