Messaging Gateway

Messaging Gateway exposes an application-friendly request/response method while hiding message channel and envelope plumbing.

var gateway = MessagingGateway<PaymentAuthorizationRequest, PaymentAuthorizationDecision>
    .Create("payment-authorization-gateway")
    .SendTo(requestChannel)
    .Handle((message, context) => Message<PaymentAuthorizationDecision>.Create(decision))
    .Build();

var result = gateway.Invoke(new PaymentAuthorizationRequest("ORDER-100", 42.50m));

Use it when application services should call a typed API while the implementation still sends a message through a channel and handles a message-shaped response. The gateway reports channel rejection explicitly so callers can distinguish backpressure from business decisions.

The source-generated path uses [GenerateMessagingGateway] and [MessagingGatewayHandler]. Import the payment example through AddPaymentMessagingGatewayDemo() or AddPatternKitExamples().