private void propagatePerSourceQueryProperties(Query original, Query outgoing, Window window,
                                                   String sourceName, String providerName) {
        outgoing.setHits(window.hits);
        outgoing.setOffset(window.offset);
        original.properties().listProperties(CompoundName.fromComponents("provider", providerName))
                .forEach((k, v) -> outgoing.properties().set(k, v));
        original.properties().listProperties(CompoundName.fromComponents("source", sourceName))
                .forEach((k, v) -> outgoing.properties().set(k, v));
    }
The name of the query property containing the source name added to the query to each source by this
container-search/src/main/java/com/yahoo/search/federation/FederationSearcher.java