History of Pool::keep 2 changes

In crates/flow/src/cache.rs, lines 146–163 on ed4aef8b70ca73c382d749781ca0fb768997d4da20802ac4ceba96b144dc3baa. 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.