src/main/java/io/reactivex/Flowable.java
@CheckReturnValue
    @BackpressureSupport(BackpressureKind.PASS_THROUGH)
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Flowable<T> doAfterNext(Consumer<? super T> onAfterNext) {
        ObjectHelper.requireNonNull(onAfterNext, "onAfterNext is null");
        return RxJavaPlugins.onAssembly(new FlowableDoAfterNext<T>(this, onAfterNext));
    }
@CheckReturnValue
    @BackpressureSupport(BackpressureKind.PASS_THROUGH)
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Flowable<T> doAfterNext(Consumer<? super T> onAfterNext) {
        ObjectHelper.requireNonNull(onAfterNext, "onAfterNext is null");
        return RxJavaPlugins.onAssembly(new FlowableDoAfterNext<T>(this, onAfterNext));
    }
Calls the specified consumer with the current item after this item has been emitted to the downstream.
<p>Note that the {@code onAfterNext} action is shared between subscriptions and as such
should be thread-safe.
<dl>
<dt><b>Backpressure:</b></dt>
<dd>The operator doesn't interfere with backpressure which is determined by the source {@code Publisher}'s backpressure
behavior.</dd>
<dt><b>Scheduler:</b></dt>
<dd>{@code doAfterNext} does not operate by default on a particular {@link Scheduler}.</dd>
<dt><b>Operator-fusion:</b></dt>
<dd>This operator supports normal and conditional Subscribers as well as boundary-limited
synchronous or asynchronous queue-fusion.</dd>
</dl>
<p>History: 2.0.1 - experimental
@param onAfterNext the Consumer that will be called after emitting an item from upstream to the downstream
@return the new Flowable instance
@since 2.1