CKSyncEngine doesn't fetch changes when saving or deleting CKShare

I've noticed that saving a `CKShare` using `CKDatabase` directly or deleting a `CKShare` via `UICloudSharingController` doesn't cause `CKSyncEngine` to fetch new changes (nor include them in updates when you call `CKSyncEngine.fetchChanges`) until the app is relaunched.

Is there a recommended way for dealing with `CKShare` together with `CKSyncEngine`?

Start by reproducing the CKSyncEngine behavior after saving a CKShare through CKDatabase and deleting one through UICloudSharingController, then call CKSyncEngine.fetchChanges and compare the results before and after relaunch. Done means identifying the supported handling for CKShare changes or documenting a confirmed fix for the missing updates.

Written by the indexing model from the issue text.