Tools and libraries that simplify RxJava in Android in Android?

// Example usage of RxJava with Retrofit
Retrofit retrofit = new Retrofit.Builder()
        .baseUrl("https://api.example.com/")
        .addConverterFactory(GsonConverterFactory.create())
        .build();

ApiService apiService = retrofit.create(ApiService.class);

apiService.getData()
    .subscribeOn(Schedulers.io())
    .observeOn(AndroidSchedulers.mainThread())
    .subscribe(new Observer() {
        @Override
        public void onSubscribe(Disposable d) {
            // Do something on subscribe
        }

        @Override
        public void onNext(Data data) {
            // Handle the received data
        }

        @Override
        public void onError(Throwable e) {
            // Handle errors
        }

        @Override
        public void onComplete() {
            // Do something on complete
        }
    });