History of Hub::checkpoint 1 change

In crates/flow/src/runner.rs, lines 252–265 on e6949d87205b25ba552afd5865dc144149d4dc8a45031cf177ba3777554de2f6. 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 252,265:crates/flow/src/runner.rs.