History of Engine::tick 2 changes

In crates/backdrop/src/lib.rs, lines 102–129 on 5501b1c657b282af52ee33f594c4f7aabd7965bda9d50ae67c4c0ab42d3b12db. 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 102,129:crates/backdrop/src/lib.rs.