private SearchInvoker getSearchInvoker(Query query) {
        return dispatcher.getSearchInvoker(query, this);
    }
Returns an invocation object for use in a single search request. The specific implementation returned
depends on query properties with the default being an invoker that interfaces with a dispatcher
on the same host.
container-search/src/main/java/com/yahoo/prelude/fastsearch/IndexedBackend.java