如何在完成数组中的第一个请求后发送请求 (Kotlin)

Question

我有一个布局，我在其中收集数组中的数据，并在此数组上发送创建发票的请求。我现在的问题是请求是同时发送的，并且发票没有正确创建。我想让它结束一个请求，然后只有第二个请求结束。谢谢！

活动中：

val preHawbCount: Int = preHawbList.count()
if (preHawbCount > 0) {
   for (index in preHawbList.indices) {
        presenter.createHawb(preHawbList[index])
   }
}

主持人：

fun createHawb(hawb: HawbCourierActivity.HawbCourier) {
        val disposable = networkApi.createHawb(
                hawb.aircompany,
                airportId,
                hawb.to_airport_id,
                hawb.sender_correspond_id,
                hawb.sender_correspond_id,
                hawb.flight_name,
                hawb.departure_date,
                userId,
                hawb.place_count,
                hawb.weight,
                hawb.eli_pcs,
                hawb.eli_weight
        )
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .doOnSubscribe { viewState.showDialog() }
                .doOnTerminate { viewState.dismissDialog() }
                .subscribe({
                    if (!it.isSuccessful) {
                        viewState.showSendErrorAction("Ошибка при получении данных")
                    }
                }, { throwable ->
                    Log.e("network problem", throwable.message)
                    throwable.printStackTrace()
                    viewState.showSendErrorAction(throwable.message.toString())
                })
        compositeDisposable.add(disposable)
    }