Nullability in C#

C# 9 continues to take on the billion-dollar mistake by building on top of the nullable reference support added in C# 8. These changes to nullable reference types incorporate all the feedback we've gotten from our customers who've adopted nullable reference types into their codebase. In this talk we're going to explore nullable reference types in C#, particularly the work done in C# 9, the progress in null annotating the .NET SDK as well as the challenges and techniques in adopting null annotations into existing code bases.