PUBLISH_BLOCKED — MoQT draft-18 §10.20.

The publisher sends the PUBLISH_BLOCKED control message to indicate it cannot send a PUBLISH message to initiate a new Subscription for a Track in the SUBSCRIBE_TRACKS's Track Namespace. All PUBLISH_BLOCKED messages are in response to a SUBSCRIBE_TRACKS, so only the namespace tuples after the 'Track Namespace Prefix' are included in the 'Track Namespace Suffix'.

PUBLISH_BLOCKED Message {
  Type (vi64) = 0xF,
  Length (16),
  Track Namespace Suffix (..),
  Track Name Length (vi64),
  Track Name (..),
}

Figure 22: MOQT PUBLISH_BLOCKED Message

Track Namespace Suffix: Specifies the final portion of a track's namespace as defined in Section 2.4.1. The namespace begins with the 'Track Namespace Prefix' specified in Section 10.19.
Track Name: Identifies the track name as defined in (Section 2.4.1).