History of pack 1 change

In crates/flow/src/checkpoint.rs, lines 62–93 on 6f66e397539c2eb66fbb3522121b0add52221a43219e9834a4f1773d584ccb45. 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 62,93:crates/flow/src/checkpoint.rs.