History of HubBackend::block 2 changes

In crates/hub/src/protocol.rs, lines 49–51 on c5f3bde466d11d2f876de714c624f81cdd0aeb66c1e4472251b66212f076b112. 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 49,51:crates/hub/src/protocol.rs.