private boolean documentTypeIntersectionIsNonEmpty(Set<String> restrict, SearchChainInvocationSpec target) {
        for (String documentType : target.schemas) {
            if (restrict.contains(documentType))
                return true;
        }

        return false;
    }
Returns true if we are requested to keep executing a target longer than we're waiting for it.
This is useful to populate caches inside targets.
container-search/src/main/java/com/yahoo/search/federation/FederationSearcher.java