Difference between Asynchronous Event Handler and Synchronous Event Handler in Sharepoint

Difference between Asynchronous Event Handler and Synchronous Event Handler in Sharepoint

S.No	Asynchronous Event Handler(AEH)	Synchronous Event Handler(SEH)
1	When it fires: AEH will fire after the event is completed.	When it fires: SEH will work before the event is completed
2	Event Cancellation: It is not possible to cancel the event from AEH.	Event Cancellation: SEH are mostly used to stop the event from completion in order to validate few things. It means we can cancel the event using SEH
3	Method Names Identification: AEH method names will end with -ed. e.g.ItemAdded, ItemUpdated are AEH methods.	Method Names Identification: SEH methods has their method names ending with -ing. e.g. ItemAdding, ItemUpdating are SEH methods
4	To add/modify list fields values: Not Possible as it fires after the completion of event.	To add/modify list fields values: Possible