History of Server::backend 1 change

In crates/oxy-server/src/lib.rs, lines 187–189 on show-stat. 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 187,189:crates/oxy-server/src/lib.rs.