fun writeToFile(response: Response<ResponseBody>, file: File): Single<ListenableWorker.Result> {
        return Single.create { emitter ->
            val bufferedSource = response.body()?.source()
            val bufferedSink = file.sink().buffer()

            bufferedSource?.use { source ->
                bufferedSink.use { sink ->
                    sink.writeAll(source)
                }
            } ?: throw IllegalArgumentException("Response is NULL")
            emitter.onSuccess(ListenableWorker.Result.success())
        }
    }