src/main/java/io/reactivex/Single.java
@CheckReturnValue
    @NonNull
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Single<T> doAfterSuccess(Consumer<? super T> onAfterSuccess) {
        ObjectHelper.requireNonNull(onAfterSuccess, "onAfterSuccess is null");
        return RxJavaPlugins.onAssembly(new SingleDoAfterSuccess<T>(this, onAfterSuccess));
    }
@CheckReturnValue
    @NonNull
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Single<T> doAfterSuccess(Consumer<? super T> onAfterSuccess) {
        ObjectHelper.requireNonNull(onAfterSuccess, "onAfterSuccess is null");
        return RxJavaPlugins.onAssembly(new SingleDoAfterSuccess<T>(this, onAfterSuccess));
    }
Calls the specified consumer with the success item after this item has been emitted to the downstream.
<p>
<img width="640" height="460" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.doAfterSuccess.png" alt="">
<p>
Note that the {@code doAfterSuccess} action is shared between subscriptions and as such
should be thread-safe.
<dl>
<dt><b>Scheduler:</b></dt>
<dd>{@code doAfterSuccess} does not operate by default on a particular {@link Scheduler}.</dd>
</dl>
<p>History: 2.0.1 - experimental
@param onAfterSuccess the Consumer that will be called after emitting an item from upstream to the downstream
@return the new Single instance
@since 2.1