History of checkpoint 1 change

In crates/hub/src/flow.rs, lines 1455–1471 on 8306eca4e4a3347a39de4baeaa83e7c7270fa356998bd66b6923b4338a5d2373. 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 1455,1471:crates/hub/src/flow.rs.