使用Transformations.map从ViewModel观察我的存储库中的LiveData似乎不起作用

Question

尤其是我的存储库中有这些LiveData对象

val liveDataA : MutableLiveData<List<ProfileApiData.A>> = MutableLiveData()
val liveDataB : MutableLiveData<List<ProfileApiData.B>> = MutableLiveData()
val liveDataC : MutableLiveData<ProfileApiData.C?> = MutableLiveData()

...我打算在所述存储库中使用以下方法进行更新。

suspend fun fetchProfile() {
    val profileDataApi = userApi.getProfile()

    liveDataA.postValue( profileDataApi.a )
    liveDataB.postValue( profileDataApi.b )
    liveDataC.postValue( profileDataApi.c )

    dao.insertProfile(profileDataApi.asEntity)
}

在引用它的ViewModel中，我使用了以下方法：

private fun getLiveDataAAsEntities() : LiveData<List<AEntity>> {
    return Transformations.map(userRepository.liveDataA) {
        val entities = it.entities
        liveDataARVDataSource.swapData( entities )

        Trace.i("A map result ${entities.size}")

        return@map entities
    }
}

private fun getLiveDataBAsEntities() : LiveData<List<BEntity>> {
    return Transformations.map(userRepository.liveDataB) {
        val entities = it.entities
        liveDataBRVDataSource.swapData( entities )

        Trace.i("B map result ${entities.size}")

        return@map entities
    }
}

private fun getLiveDataCAsEntity() : LiveData<ProfileApiData.CEntity?> {
    return Transformations.map(userRepository.liveDataC) {
        Trace.i("C map result $it")

        if (it?.url.isEmpty) {
            presenters.forEach {
                it.onLiveDataCParsed(false, "", -1, -1, "", "")
            }
        } else {
            it?.let { entityC ->
                presenters.forEach {
                    it.onLiveDataCParsed(true, entityC.url, entityC.stamp.countAllStamp, entityC.stamp.sisa, entityC.stamp.prize, entityC.dashCoverUrl)
                }
            }
        }

        return@map it
    }
}

fun updateProfile() {
    viewModelScope.launch(Dispatchers.Main) {

        val updateProfileTask = async(Dispatchers.IO) {

            Trace.i("start fetch profile")

            userRepository.fetchProfile()
        }

        updateProfileTask.await()

        liveDataAEntity = getLiveDataAAsEntities()
        liveDataBEntity = getLiveDataBAsEntities()
        liveDataCEntity = getLiveDataCAsEntities()

        Trace.i("finished fetch profile ${userRepository.liveSchedules.value} ${liveSchedules.value}\n$${movies.value}\n${userRepository.hutPlaydayObject.value} ${hutPlaydayObject.value}")

        presenters.forEach {
            it.onUpdateProfileFinished()
        }
    }
}

...以“观察”存储库中的liveDataA，liveDataB和liveDataC。注意：.entities是自定义地图函数。

但是，finished fetch profile日志值仍然返回null，甚至没有调用map函数中的日志函数。

这种Transformations.map的实现有问题吗？