History of HubBackend::block 2 changes

In crates/hub/src/protocol.rs, lines 45–47 on db72849cd22e82e6160e21528548f9766cf4b10867415ce1b2fe177bfa05e71f. 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 45,47:crates/hub/src/protocol.rs.