A topic for an endpoint is not created until the endpoint publishes it's first message

[CallumHibbert]

A topic for an endpoint is not created until the endpoint publishes it's first message, so another endpoint can't subscribe until after a message has been published by the endpoint.

This means you have to jump through hoops to set-up subscriptions or risk losing messages (because an endpoint wasn't able to subscribe).

If an endpoint is a publisher, it should probably ensure it's topic exists when it starts up.

[CallumHibbert]

Same as this: Particular/NServiceBus.Azure#20