public void destroy() {
        if (!destroyed.getAndSet(true)) {
            mbus.destroy();
            mbus = null;
            net = null;

            slobrok.stop();
            slobrok = null;
        }
    }
Sets the destroyed flag to true. The very first time this method is called, it cleans up all its dependencies.
Even if you retain a reference to this object, all of its content is allowed to be garbage collected.
documentapi/src/test/java/com/yahoo/documentapi/messagebus/protocol/test/PolicyTestFrame.java