INFO if that does not work, sync folders where no stat can be found only
once a hour, include PR_CONTENT_COUNT, PR_CONTENT_UNREAD and
PR_DELETED_MSG_COUNT into stat to reflect all kind of changes,
SyncCollection->CheckForChanges() compares folderstats for changes when
initiating, in case of error remove the folderstat to ensure folder is
synchronized next Sync request, remove 'savestate' functionality as it
is not used.

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