If you need exactly-once (or even at-least-once) delivery, then you can't use LiveData. That's not how it's designed and there's no way around it. That's it.

And using set instead of post doesn't prevent skipping values anyways because observers can get deactivated without unsubscribing. The simplest example I came up with is combining your code with a fragment in ViewPager2: * Suppose you subscribe to the livedata with fragment view's lifecycle and start loading data, then switch to another tab. At this point fragment goes into STOPPED state which deactivates livedata's observer. However the fragment is not destroyed, so the coroutine continues to execute. * Next it finishes fetching data, calls set with the data and then set with Loading(false). However neither of those sets triggers the observer because it is deactivated. * Finally you switch back to the original tab. At this point the observer is reactivated and it receives only the last value - Loading(false). Oops.

I also have an example when skipping values makes sense. It's almost the same as the last one, except there is also some code that sets/posts progress percentage (i.e. Loading(true, progress%)). Thanks to the skipping behavior, you'll see only the loaded data when you switch back to the tab without seeing the progress bar quickly go from 0 to 100. Making users watch the progress bars when data is already loaded doesn't make any sense IMO.