History of Pool::keep 3 changes

In crates/flow/src/cache.rs, lines 231–265 on 42c8e2f4219f132df0776b4e53fa34de3055f3ca2b9d9933a0c1524ff1880894. 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.