History of Engine::tick 2 changes

In crates/backdrop/src/lib.rs, lines 107–134 on c4027e038d2533aa595eef44c4c8e7b9c6ee08efed3b65a9d76a4a14aa5ff38c. 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.