Sometimes events on Salesforce need to be handled by an external system due to the scale or type of process being executed. Consider the use case of a user in Salesforce needing to get pricing for an order they are building in Salesforce while on the phone with a customer. The pricing logic already exists in a third-party system. Instead of recreating this logic in Salesforce, it will be leveraged by making a request of the third-party system. The response, in this case the pricing, will be returned and stored back in Salesforce. What is the optimal solution?