private void traceTargets(Query query, Collection<Target> targets) {
        int traceFederationLevel = 2;
        if ( ! query.getTrace().isTraceable(traceFederationLevel)) return;
        query.trace("Federating to " + targets, traceFederationLevel);
    }
TODO This is probably a dirty hack for bug 4711376. There are probably better ways.
But I will leave that to trd-processing@

@param group the merging hitgroup to be updated if necessary
@param orderer the per provider hit orderer
@return he hitorderer chosen
container-search/src/main/java/com/yahoo/search/federation/FederationSearcher.java