History of Engine::tick 2 changes

In crates/backdrop/src/lib.rs, lines 107–134 on 4f40eed0588f55ff8e73d82b0f9cdc24a5864cb105bd3cbb8bab35126c9580fb. 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.