History of Engine::tick 2 changes

In crates/backdrop/src/lib.rs, lines 107–134 on 810896d41be780e42f5a7b63a33edcf49b94a106fce7e31212202a5f922b13ac. 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.