@Override
    public void deliverMessage(Message message, String session) {
        // Send to first owner which has registered this session, or fall back to first attached owner (for rejection).
        NetworkOwner owner = sessions.getOrDefault(session, owners).peek();
        if (owner == null) { // Should not happen.
            log.warning(this + " received message '" + message + "' with no owners attached");
            message.discard();
        }
        else
            owner.deliverMessage(message, session);
    }
Returns a network multiplexer with a single {@link NetworkOwner}, which shuts down when this owner detaches.
messagebus/src/main/java/com/yahoo/messagebus/network/NetworkMultiplexer.java