History of HubBackend::block 2 changes

In crates/hub/src/protocol.rs, lines 59–61 on 1870e4fa98086468364a61d2fa556f7fe5913bccd31404c75d8836cb12097d6c. 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.