A microservices$-$based architecture for an e$-$commerce platform is in the design phase. A core requirement is to ensure that the system can handle eventual consistency while ensuring that the platform's various services remain loosely coupled. Two services, Order Service and Inventory Service, need to communicate regarding the availability of products.

When a customer places an order; the Order Service needs to check if the product is in stock using the Inventory Service. However, the design must ensure that even if the inventory Service is temporarily unavailable, the Order Service can still accept orders, albeit with some potential delay in processing.

Which of the following communication patterns is most suitable to ensure that the services remain decoupled and the system handles eventual consistency?