A publisher sends Objects matching a subscription on Data Streams or Datagrams and sends Objects matching a FETCH request on one Data Stream.
Unidirectional stream types are defined in Section 3.4. Data streams use SUBGROUP_HEADER or FETCH_HEADER types.
All MOQT datagrams start with a variable-length integer indicating the type of the datagram. See Section 10.3.1.
An endpoint that receives an unknown datagram type MUST close the session.
Every Object has a 'Object Forwarding Preference' and the Original Publisher MAY use both Subgroups and Datagrams within a Group or Track.