History of HubBackend::block 2 changes

In crates/hub/src/protocol.rs, lines 51–53 on 4da8b828a822b183cb76ba74689bd0173c244e19385d8c51ddb65facf7141cb2. 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.