private val DEF_HTTP_RETRY_LOGIC = { errors : Observable<out Throwable> ->
    errors.zipWith(
          Observable.range(1, DEF_HTTP_RETRY_COUNT + 1),
          { error, attempt -> Pair(error, attempt) }
        )
        .flatMap {
          val error = it.first
          val attempt = it.second
          Timber.d("Error: $error during attempt $attempt")

          if (attempt <= DEF_HTTP_RETRY_COUNT && error is RetrofitError
              && error.kind == RetrofitError.Kind.NETWORK) {
            Timber.d("Retrying...")
            Observable.timer(attempt.toLong(), TimeUnit.SECONDS)
          } else {
            Observable.error(error as Throwable)
          }
        }
  }