History of plan 2 changes

In crates/hub/src/diffusion.rs, lines 659–679 on 8ad8e656a3a654690a1c7577e34a8a744611e1a0119167bc3209cd5c87c18787. 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.