How to tell if a PC is rebooting

Question

I have a c# app the kicks off some other processes and those processes can kick off a reboot.  Problem is the reboot is greatly delayed because the first c# app is still running.  It will forcibly get rebooted eventually, but it delays things by about 5-8min.  So I need to put in some kind of check/hook in the c# app to see if the PC is starting a reboot process.  Any ideas?