Was Neyman's 1923 Potential Outcomes Notation Originally for Continuous Treatments?

I am in Cologne Germany at GESIS teaching a five day workshop on diff-in-diff. On the first day, roughly four or five people requested that I cover continuous diff-in-diff. As I hadn’t planned to, I’ve been trying to get the last part of the Callaway, Goodman-Bacon and Sant’Anna paper prepped. I’m basically having a hard time with my attention span la…