History of HubBackend::block 2 changes

In crates/hub/src/protocol.rs, lines 68–70 on 13b27cb2200c246f36d31d83144c047a61ccd07f12b9aa61c2a69c114bb11e2b. 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.