The "Lock-Step" delivery method attempts to ensure that messages are not delivered to a service faster than the service is able to retrieve them. It does this by blocking message delivery until the receiving service picks up the message or a time-out period expires.
This is not a synchronous delivery method. It does not wait for a response or for the service to process the message. It only blocks until the message is removed from the queue by the service.
Lock-step delivery is disabled by default.