History of HubBackend::caller 2 changes

In crates/hub/src/protocol.rs, lines 58–77 on b45384c909c19ecb69915e69e0395441aaf509e1156dd94d0f38794449ec26b1. 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.