NSApplication.TerminateReply.terminateLater
Declaration
case terminateLaterDiscussion
It may be OK to proceed with termination later. Returning this value causes Cocoa to run the run loop in the NSModalPanelRunLoopMode until your app subsequently calls reply(toApplicationShouldTerminate:) with the value true or false. This return value is for delegates that need to provide document modal alerts (sheets) in order to decide whether to quit.