22/ Moving up the call chain: Application code is like high-level infrastructure. It delegates, probably to the high-level infrastructure, which turns around and delegates to low-level infrastructure.
That raises the question: how do you TEST things that eventually delegate to low-level infrastructure and talk to the outside world? Without using mocks, stubs, or spies?
And that's where Nullables come in.
("Finally!" some of you say. "Won't this guy ever shut up?" the rest of you say.)