Flowables (RxJava2) with Realm

RxJava2 + Realm

var tasksList: RealmList<Tasks>
tasksList = RealmList()

getPendingTasks(3)
              .flatMapIterable { it -> it }
              .concatMap { task ->
                  getPendingSubTasks(task.id)
                  .doOnNext {
                      //Here we are binding subtasks to individual task item
                      bindChildTasks(it, task)
                  }
              }.toList()
              .subscribeOn(looperScheduler)
              .unsubscribeOn(looperScheduler)
              .observeOn(looperScheduler)
              .doOnSubscribe {
                  showLoading("")
              }.subscribeBy(  // named arguments for lambda Subscribers
                      onError = {
                          it.printStackTrace()
                      }, onSuccess = {
                      /Finalized Composed list will be used on MainThread in this callback
                      loadTasks() 
                      }
              )


//Child tasks will be added using Realm transaction
fun bindChildTasks(subTaskList: List<SubTasks>, task: Tasks) {
    if (subTaskList.size > 0) {
        Realm.getDefaultInstance().executeTransaction {
            val realmList = RealmList<SubTasks>()
            realmList.addAll(subTaskList)
            task.subTasksList = realmList
        }
    }
}


//Our composed list will be fetched in this observable:
fun loadTasks() {
    getPendingTasks(3)
            .subscribeOn(AndroidSchedulers.mainThread())
            .unsubscribeOn(AndroidSchedulers.mainThread())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribeBy(  // named arguments for lambda Subscribers
                    onNext = {
                        tasksList.addAll(it)
                    },
                    onError = {
                        it.printStackTrace()
                    },
                    onComplete = {
                        //We populate our RecyclerView here
                        setUpAdapter()
                        hideLoading()
                    }
            )
}