private static <T> List<Target> getAdditionalTargets(Query query, Execution execution, TargetSelector<T> targetSelector) {
        if (targetSelector == null) return List.of();

        ArrayList<Target> result = new ArrayList<>();
        for (FederationTarget<T> target: targetSelector.getTargets(query, execution.searchChainRegistry()))
            result.add(new CustomTarget<>(targetSelector, target));

        return result;
    }
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