History of tiers 4 changes

In crates/flow/src/runner.rs, lines 532–553 on cc462b56fbbb935df73234cf7ae0ac8de8a839549a4aa7aa26d4b2d038edbc12. 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 532,553:crates/flow/src/runner.rs.