// countdown 10
val observer = object : DisposableObserver<Long>() {
    override fun onComplete() {
        Timber.d("onComplete")
        isLoading.value = false
    }

    override fun onNext(t: Long) {
        Timber.d("onNext:$t")

    }

    override fun onError(e: Throwable) {
        Timber.d("onError:%s",e.message)
        isLoading.value = false
    }

}

val timeCount = 10.toLong()

Observable.interval(0,1,TimeUnit.SECONDS)
    .subscribeOn(Schedulers.io())
    .observeOn(AndroidSchedulers.mainThread())
    .map {
        timeCount-it
    }
    .take(timeCount)
    .doOnSubscribe {
        isLoading.value = true
    }
    .subscribe(observer)