History of HubBackend::block 2 changes

In crates/hub/src/protocol.rs, lines 59–61 on e71583501b1d28e733327b161531c4e6899cdf30605e7dfa27dc6b32733b98ba. 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.