History of HubBackend::caller 3 changes

In crates/hub/src/protocol.rs, lines 62–88 on ef20fdc14e8b65290f49367c71f7ee730c287e5ae61513eaf82616dd5329b1ed. 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.