That's indeed true for the default interface implementation, but I believe for nullability it's just compiler warnings. At runtime, nothing will be left in the IL for this. It just isn't possible to do that and maintain backward compatibility
26 karma · joined February 19, 2012
Here's some more info (although outdated): https://en.wikipedia.org/wiki/Coroutine#Implementations_for_...
Thanks, glad you enjoyed it!