History of HubBackend::block 2 changes

In crates/hub/src/protocol.rs, lines 68–70 on 1c4ad601ef9d3108d4a3ea574d8e57e733a7404de1e197e6f35b6e692c6bfb7d. 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.