History of Engine::tick 2 changes

In crates/backdrop/src/lib.rs, lines 107–134 on c08cec372c811493ed7a0232a5681f8c5895aecc62d6549b0ec5bbf0324b3ad6. 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.