History of Pool::keep 2 changes

In crates/flow/src/cache.rs, lines 146–163 on eaad903bb26649f4fcadcd3a889196a460b461432a8cb85272594d7c65c5bfaf. 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 146,163:crates/flow/src/cache.rs.