SampleViewModel.kt

class SampleViewModel : ViewModel() {
    val sampleData = UiAsyncLoadLiveData<String> {
        value = try {
            async(coroutineContext + CommonPool) {
                "very long time process!"
            }.await()
        } catch (e: CancellationException) {
            null
        }
    }
}

UiAsyncLoadLiveData.kt

class UiAsyncLoadLiveData<T>(
    private val onActive: suspend UiAsyncLoadLiveData<T>.() -> Unit
) : MutableLiveData<T>() {

    private var job = EMPTY_JOB

    override fun onActive() {
        if (job.isActive || value != null) {
            return
        }
        job = launch(UI) {
            onActive.invoke(this@UiAsyncLoadLiveData)
        }
    }

    override fun onInactive() {
        job.cancel()
    }

    fun retry(resetValue: Boolean = true) {
        if (resetValue) {
            value = null
        }
        if (hasActiveObservers()) {
            if (job.isActive) {
                job.cancel()
            }
            onActive()
        }
    }
}