adds notes

src/Umbraco.Web/PublishedCache/NuCache/PublishedSnapshotService.cs

@@ -868,7 +868,20 @@ namespace Umbraco.Web.PublishedCache.NuCache
                 //Since the models in the cache are based on these actual classes, all of the objects in the cache need to be updated
                 //to use the newest version of the class.
 
-                // These can be run side by side in parallel
+                // NOTE: Ideally this can be run on background threads here which would prevent blocking the UI
+                // as is the case when saving a content type. Intially one would think that it won't be any different
+                // between running this here or in another background thread immediately after with regards to how the
+                // UI will respond because we already know between calling `WithSafeLiveFactoryReset` to reset the PureLive models
+                // and this code here, that many front-end requests could be attempted to be processed. If that is the case, those pages are going to get a
+                // model binding error and our ModelBindingExceptionFilter is going to to its magic to reload those pages so the end user is none the wiser.
+                // So whether or not this executes 'here' or on a background thread immediately wouldn't seem to make any difference except that we can return
+                // execution to the UI sooner.
+                // BUT!... there is a difference IIRC. There is still execution logic that continues after this call on this thread with the cache refreshers
+                // and those cache refreshers need to have the up-to-date data since other user cache refreshers will be expecting the data to be 'live'. If
+                // we ran this on a background thread then those cache refreshers are going to not get 'live' data when they query the content cache which
+                // they require.
+
+                // These can be run side by side in parallel.
 
                 Parallel.Invoke(
                     () =>