History of HubBackend::caller 2 changes

In crates/hub/src/protocol.rs, lines 58–77 on 3f4b0ea6eabf3074989245c59133f905ada2b63e707ae18eac5082b97c700339. 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.