History of Engine::tick 2 changes

In crates/backdrop/src/lib.rs, lines 107–134 on 439ecd8708a13ffd255537fab186ab2b3f49ef9f6a8684d55b0b294d434d6ab7. 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 107,134:crates/backdrop/src/lib.rs.