History of HubBackend::block 2 changes

In crates/hub/src/protocol.rs, lines 59–61 on c21ef37dd4a0641cafb7fe4cf430093934e416d10b582d4183d9c30f722f42e5. 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 59,61:crates/hub/src/protocol.rs.