History of HubBackend::block 2 changes

In crates/hub/src/protocol.rs, lines 68–70 on a2a96bf2145547ea848d22a6d58489572763db661cf161232fb315e618a4be8f. 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 68,70:crates/hub/src/protocol.rs.