events = [OrderCreated(...), OrderPaid(...), OrderShipped(...)]

def rebuild(events):
    state = {}
    for e in events: state = apply(state, e)
    return state

Choreo: OrderCreated → Payment → Shipping
Orchestrator: ProcessPayment() → ShipOrder()

// Producer
producer.send({ topic: 'orders', messages: [{ ... }] });

// Consumer
consumer.run({
  eachMessage: async ({ message }) => {
    handleEvent(JSON.parse(message.value));
  }
});

class OrderCreatedEvent {
    public function __construct(public Order $order) {}
}

class SendEmail {
    public function __invoke(OrderCreatedEvent $e) {
        $this->mailer->send($e->order->email, 'Confirmation');
    }
}