src/main/java/io/reactivex/Single.java
@BackpressureSupport(BackpressureKind.FULL)
    @CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Flowable<T> concatWith(SingleSource<? extends T> other) {
        return concat(this, other);
    }
@BackpressureSupport(BackpressureKind.FULL)
    @CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Flowable<T> concatWith(SingleSource<? extends T> other) {
        return concat(this, other);
    }
@ BackpressureSupport ( BackpressureKind . FULL ) @ CheckReturnValue @ SchedulerSupport ( SchedulerSupport . NONE ) public final Flowable < T > concatWith ( SingleSource < ? extends T > other ) { return concat ( this , other ) ; }
Returns a Flowable that emits the item emitted by the source Single, then the item emitted by the
specified Single.
<p>
<img width="640" height="335" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concatWith.png" alt="">
<dl>
<dt><b>Backpressure:</b></dt>
<dd>The returned {@code Flowable} honors the backpressure of the downstream consumer.</dd>
<dt><b>Scheduler:</b></dt>
<dd>{@code concatWith} does not operate by default on a particular {@link Scheduler}.</dd>
</dl>

@param other
a Single to be concatenated after the current
@return a Flowable that emits the item emitted by the source Single, followed by the item emitted by
{@code t1}
@see <a href="http://reactivex.io/documentation/operators/concat.html">ReactiveX operators documentation: Concat</a>
Returns a Flowable that emits the item emitted by the source Single then the item emitted by the specified Single . <p > <img width = 640 height = 335 src = https : // raw . github . com / wiki / ReactiveX / RxJava / images / rx - operators / Single . concatWith . png alt = > <dl > <dt > <b > Backpressure : < / b > < / dt > <dd > The returned { @code Flowable } honors the backpressure of the downstream consumer . < / dd > <dt > <b > Scheduler : < / b > < / dt > <dd > { @code concatWith } does not operate by default on a particular { @link Scheduler } . < / dd > < / dl >