MOQT requires a long-lived and stateful session. However, a service provider needs the ability to shutdown/restart a server without waiting for all sessions to drain naturally, as that can take days for long-form media. MOQT enables proactively draining sessions via the GOAWAY message (Section 8.4).
The server sends a GOAWAY message, signaling the client to establish a new session and migrate any active subscriptions. The GOAWAY message optionally contains a new URI for the new session, otherwise the current URI is reused. The server SHOULD terminate the session with 'GOAWAY Timeout' after a sufficient timeout if there are still open subscriptions or fetches on a connection.
When the server is a subscriber, it SHOULD send a GOAWAY message to downstream subscribers prior to any UNSUBSCRIBE messages to upstream publishers.
After the client receives a GOAWAY, it's RECOMMENDED that the client waits until there are no more active subscriptions before closing the session with NO_ERROR. Ideally this is transparent to the application using MOQT, which involves establishing a new session in the background and migrating active subscriptions and announcements. The client can choose to delay closing the session if it expects more OBJECTs to be delivered. The server closes the session with a 'GOAWAY Timeout' if the client doesn't close the session quickly enough.