History of HubBackend::block 2 changes

In crates/hub/src/protocol.rs, lines 51–53 on e15409084ed6de68f460f830d74c15458dcee9ab20a6c8dd39145d04a895d54e. 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 51,53:crates/hub/src/protocol.rs.