History of preflight 2 changes

In crates/flow/src/runner.rs, lines 517–541 on 28cc603f737d188c5cb531f955ad89368f6e12c470527642b95634ac9283ba61. 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 517,541:crates/flow/src/runner.rs.