@Override
    public void registerSession(String session) {
        register.registerName(identity.getServicePrefix() + "/" + session);
    }
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