History of HubBackend::caller 3 changes

In crates/hub/src/protocol.rs, lines 62–88 on 705d11b01a2cdb600eb543a73fa3eae62acf83df1e95d5ea0327e27e06be4480. 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.