History of plan 2 changes

In crates/hub/src/diffusion.rs, lines 659–679 on 5588bb3631d2016d3b5365c4665ded2f18ab9982fc70daf1599091cc90077ddb. Every change that wrote or deleted one of these lines, or deleted a line from between them. Exact, because each line keeps its identity across edits; edits elsewhere in the file are not here. Also: oxy log -L 659,679:crates/hub/src/diffusion.rs.