The new LiveData can be used as a replacement for RxJava\'s observables in some scenarios. However, unlike Observable, LiveData has no callback for
In one of Google's sample apps for Android Architecture Components they wrap the LiveData emitted object in a class that can contain a status, data, and message for the emitted object.
https://github.com/googlesamples/android-architecture-components/blob/master/GithubBrowserSample/app/src/main/java/com/android/example/github/vo/Resource.kt
With this approach you can use the status to determine if there was an error.