private static Map<String, List<String>> createSchema2Clusters(SchemaInfo schemaInfo) {
        Map<String, List<String>> schema2Clusters = new HashMap<>();
        for (Cluster cluster : schemaInfo.clusters().values()) {
            for (String schema : cluster.schemas()) {
                schema2Clusters.computeIfAbsent(schema, key -> new ArrayList<>()).add(cluster.name());
            }
        }
        return schema2Clusters;
    }
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