Method flatMapMaybe

src/main/java/io/reactivex/rxjava3/core/Single.java:3476–3482

Returns a Maybe that is based on applying a specified function to the item emitted by the current Single, where that function returns a MaybeSource. <img width="640" height="191" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.flatMapMaybe.png

(@NonNull Function<? super T, ? extends MaybeSource<? extends R>> mapper)

     * @see <a href="http://reactivex.io/documentation/operators/flatmap.html">ReactiveX operators documentation: FlatMap</a>
     */
    @CheckReturnValue
    @NonNull
    @SchedulerSupport(SchedulerSupport.NONE)
    public final <@NonNull R> Maybe<R> flatMapMaybe(@NonNull Function<? super T, ? extends MaybeSource<? extends R>> mapper) {
        Objects.requireNonNull(mapper, "mapper is null");
        return RxJavaPlugins.onAssembly(new SingleFlatMapMaybe<>(this, mapper));
    }

    /**
     * Returns a {@link Flowable} that emits items based on applying a specified function to the item emitted by the