Rx.Single timer

The timer processing introduce the following two of Pattern in Rx.Single.

Repeat until OnError

callSingle().toObservable()
    .subscribeOn(Schedulers.io())
    .observeOn(AndroidSchedulers.mainThread())
    .repeatWhen { it.flatMap({ Observable.timer(50, TimeUnit.SECONDS)}) }
    .subscribe({
        doStuff()
    })

Repeat until OnSuccess

callSingle().toObservable()
    .subscribeOn(Schedulers.io())
    .observeOn(AndroidSchedulers.mainThread())
    .retryWhen { it.flatMap({ Observable.timer(50, TimeUnit.SECONDS)}) }
    .subscribe({
        doStuff()
    })

There is a need to convert once from Single to Observable