History of HubBackend::block 2 changes

In crates/hub/src/protocol.rs, lines 107–109 on acb8d109e981553b233a60ad4df83f8f868e9ecb88214c56cd927d7f4944a1a4. 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 107,109:crates/hub/src/protocol.rs.