private FutureResult searchAsynchronously(Query query, Execution execution, Window window, Target target) {
        long timeout = target.federationOptions().getSearchChainExecutionTimeoutInMilliseconds(query.getTimeLeft());
        if (timeout <= 0)
            return new FutureResult(() -> new Result(query, ErrorMessage.createTimeout("Timed out before federation")), execution, query);
        Query clonedQuery = cloneFederationQuery(query, window, timeout, target);
        return new AsyncExecution(target.getChain(), execution).search(clonedQuery);
    }
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