private static boolean resolveStreaming(Set<String> sources, Map<String, Cluster> clusters) {
            if (sources.isEmpty()) return clusters.values().stream().allMatch(Cluster::isStreaming);

            var matchedClusters = sources.stream().map(source -> clusterOfSource(source, clusters)).filter(Objects::nonNull).toList();
            if (matchedClusters.isEmpty()) return false;
            return matchedClusters.stream().allMatch(Cluster::isStreaming);
        }
Looks up a field or field set by the given name or alias
in the schemas resolved for this query.

If there are several fields or field sets by this name or alias across the schemas of this session,
one is chosen by random.

@param fieldName the name or alias of the field or field set. If this is empty, the name "default" is looked up.
@return the appropriate field or empty if no field or field set has this name or alias
container-search/src/main/java/com/yahoo/search/schema/SchemaInfo.java