History of plan 2 changes

In crates/hub/src/diffusion.rs, lines 659–679 on a7aa76ac52d71a6d221ff315025cbcb5076097311c84fa9ec54c5d455402760e. 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.