History of Swarm::fetch 3 changes

In crates/flow/src/swarm.rs, lines 151–341 on 21a3ea4aab8894f35a130036a31837139627f5b0e03bf6f0180f9abc9a0be727. 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 151,341:crates/flow/src/swarm.rs.