final Route getRoute(String routeString) {
        Route route = lruRouteMap.get(routeString);
        if (route == null) {
            route = Route.parse(routeString);
            lruRouteMap.put(routeString, route);
        }
        return new Route(route);
    }
The network uses a cache of RPC targets (see {@link RPCTargetPool}) that allows it to save time by reusing open
connections. It works by keeping a set of the most recently used targets open. Calling this method forces all
unused connections to close immediately.
messagebus/src/main/java/com/yahoo/messagebus/network/rpc/RPCNetwork.java