Loop Recursion

[This is preliminary documentation and subject to change.]

An asynchronous event may modify the item that caused the event notification. This in turn may cause the same event notification for the same the item, thereby causing a recursive sink loop. You must ensure that looping does not occur. To assist event sinks in making this determination the store adds a property to the item so that the sink can stamp a GUID on the item when it receives the event. This property is persisted between event notifications. This persistence allows the sink to look for its GUID stamp to determine if a recursive loop has occurred.