src/main/java/io/reactivex/Maybe.java
@SuppressWarnings({ "rawtypes", "unchecked" })
    @BackpressureSupport(BackpressureKind.FULL)
    @CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public static <T> Flowable<T> concatArrayEager(MaybeSource<? extends T>... sources) {
        return Flowable.fromArray(sources).concatMapEager((Function)MaybeToPublisher.instance());
    }
@SuppressWarnings({ "rawtypes", "unchecked" })
    @BackpressureSupport(BackpressureKind.FULL)
    @CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public static <T> Flowable<T> concatArrayEager(MaybeSource<? extends T>... sources) {
        return Flowable.fromArray(sources).concatMapEager((Function)MaybeToPublisher.instance());
    }
Concatenates a sequence of MaybeSource eagerly into a single stream of values.
<p>
Eager concatenation means that once a subscriber subscribes, this operator subscribes to all of the
source MaybeSources. The operator buffers the value emitted by these MaybeSources and then drains them
in order, each one after the previous one completes.
<p>
<img width="640" height="489" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Maybe.concatArrayEager.png" alt="">
<dl>
<dt><b>Backpressure:</b></dt>
<dd>The operator honors backpressure from downstream.</dd>
<dt><b>Scheduler:</b></dt>
<dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
</dl>
@param <T> the value type
@param sources a sequence of MaybeSources that need to be eagerly concatenated
@return the new Flowable instance with the specified concatenation behavior