History of HubBackend::caller 2 changes

In crates/hub/src/protocol.rs, lines 58–77 on 4edcf24025cf5a00e617c4270280efb55b88a5805bc90221e7741b22e4188d35. 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 58,77:crates/hub/src/protocol.rs.