Medium_RetryWhen_4.kt

//Our function Zips error emissions with a range to limit them to 3,
// and emits a 0L with a power of 2 based delay
webservice.getRequestSingle()
  .retryWhen { errors: Flowable<Throwable> -> 
    errors.zipWith(
      Flowable.range(1,3)
      BiFunction<Throwable, Int, Int> { error: Throwable, retryCount: Int ->
        retryCount                     
      }
    ).flatMap { retryCount: Int ->
        Flowable.timer(
          Math.pow(2.toDouble(), retryCount.toDouble()).toLong(),
          TimeUnit.SECONDS
        )       
   }          
}
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe({ data -> 
     //refreshScreenWithData
  }, { error -> 
     //handle error
})

Thanks for the article.
Small typoes:

Bifunction -> BiFunction
flapMap -> flatMap

fixed