History of Pool::keep 3 changes

In crates/flow/src/cache.rs, lines 231–265 on 337afb8f604306f39990537f04b0259892164b1bf205bb374ff7b6d110b4e267. 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 231,265:crates/flow/src/cache.rs.