Better asynchronous transactions

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Something like this?

    interface AsyncTransactionTask<T> {
        Single<T> execute();
    }

    public <T> Single<T> transactionAsync(@NonNull final AsyncTransactionTask task) {
        return Single.create(new Single.OnSubscribe<Single<T>>() {
            @Override
            public void call(SingleSubscriber<? super Single<T>> subscriber) {
                subscriber.onSuccess(task.execute());
            }
        }).flatMap(new Func1<Single<T>, Single<? extends T>>() {
            @Override
            public Single<? extends T> call(Single<T> single) {
                return single;
            }
        });
    }

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I have tried some transaction APIs based on observables, but they are difficult to understand.

I'll provide a low-level interface for transactions to use them with asynchronous tasks, and transactionAsync() will be removed.