SharePoint 2013 Asynchronous event handler executing synchronously (under wpw3 instead of owstimer)

问题

I created a custom list event handler using Visual Studio 2013, for ItemAdded and ItemUpdated events. I totally expected those to execute under OWSTIMER.EXE as I do not want to add load to W3wp.exe, since the actions I need to perform in the ER will be rather heavy. However, in debug mode I noticed that it would only hit my Breakpoints by attaching to the W3wp.exe. I even configured the event receiver to be asynchronous in the XML expecting this would force them to run under OWSTimer but no luck. I strongly suspect this changed from SP2010 to SP2013. Could you guys please shed some light on this? Does anyone know whether both sync and async events execute under w3wp in SP2013?

Thanks in advance,

Martin.

来源：https://stackoverflow.com/questions/33613342/sharepoint-2013-asynchronous-event-handler-executing-synchronously-under-wpw3-i