History of Engine::tick 2 changes

In crates/backdrop/src/lib.rs, lines 107–134 on 946fe7a09faac0e57edbde6c7e68444d0ada282ddf8658f94d9a2f59bba4bb5f. 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.