To Commit or Bail
Once the three phases are complete, it is time to tell the truth database that the application has either accepted the changes or that there was an error and needs to abort the sync. It should be noted that it is possible to abort the sync session at any time by calling -cancelSyncing on the ISyncSession reference.
It is recommended that the client application save out its data store to disk or do whatever other processing is appropriate before it actually commits the changes. Once the commit back to the truth database is done, it is not possible to pull down changes from the truth again without forcing a slow sync. To commit the changes back to the truth database, simply call -clientCommittedAcceptedChanges on the ISyncSession reference.