History of HubBackend::caller 3 changes

In crates/hub/src/protocol.rs, lines 62–88 on 462f88d161ce51c4ae1c952705b35fff46170e9be8fcdab9fa5ec59ed9045437. 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 62,88:crates/hub/src/protocol.rs.