History of pack 1 change

In crates/flow/src/checkpoint.rs, lines 62–93 on 1a50d4dae89c5f7a4a69834a59cc9808c81d9f0a72d8f62c2c391d159282f766. 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.