History of HubBackend::block 2 changes

In crates/hub/src/protocol.rs, lines 51–53 on 7f5f6c056d8f8d6e1a66a185452f10303c36f5758c19fe6790af59137752708e. 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.