src/main/java/io/reactivex/Single.java
@CheckReturnValue
    @NonNull
    @SchedulerSupport(SchedulerSupport.NONE)
    public static <T> Single<T> amb(final Iterable<? extends SingleSource<? extends T>> sources) {
        ObjectHelper.requireNonNull(sources, "sources is null");
        return RxJavaPlugins.onAssembly(new SingleAmb<T>(null, sources));
    }
@CheckReturnValue
    @NonNull
    @SchedulerSupport(SchedulerSupport.NONE)
    public static <T> Single<T> amb(final Iterable<? extends SingleSource<? extends T>> sources) {
        ObjectHelper.requireNonNull(sources, "sources is null");
        return RxJavaPlugins.onAssembly(new SingleAmb<T>(null, sources));
    }
Runs multiple SingleSources and signals the events of the first one that signals (disposing
the rest).
<p>
<img width="640" height="515" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.amb.png" alt="">
<dl>
<dt><b>Scheduler:</b></dt>
<dd>{@code amb} does not operate by default on a particular {@link Scheduler}.</dd>
</dl>
@param <T> the value type
@param sources the Iterable sequence of sources. A subscription to each source will
occur in the same order as in this Iterable.
@return the new Single instance
@since 2.0