docs: private void processNodeStateEvent(NodeStateEvent event) {
      switch (stateRef.get()) {
        case BEFORE_INIT:
        case DURING_INIT:
          throw new AssertionError("Filter should not be marked ready until LBP init");
        case CLOSING:
          return; // ignore
        case RUNNING:
          for (LoadBalancingPolicy policy : policies) {
            if (event.newState == NodeState.UP) {
              policy.onUp(event.node);
            } else if (event.newState == NodeState.DOWN || event.newState == NodeState.FORCED_DOWN) {
              policy.onDown(event.node);
            } else if (event.newState == NodeState.UNKNOWN) {
              policy.onAdd(event.node);
            } else if (event.newState == null) {
              policy.onRemove(event.node);
            } else {
              LOG.warn("[{}] Unsupported event: {}", logPrefix, event);
            }
          }
          break;
      }
    }