History of dispatch 4 changes

In crates/hub/src/protocol.rs, lines 636–658 on v0.9.21. 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 636,658:crates/hub/src/protocol.rs.