History of plan 2 changes

In crates/hub/src/diffusion.rs, lines 659–679 on 0468394734e96d5db008f4e36827ed560766ae8742e0e42ed4ac7184f49242e5. 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.