History of HubBackend::block 2 changes

In crates/hub/src/protocol.rs, lines 68–70 on b9eb70fb95093d2f5542ebc2c94a199d4d7b1c7e1423f1821e20fef9021bd661. 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.