The publisher MUST send exactly one FETCH_OK or REQUEST_ERROR in response to a FETCH.
A subscriber keeps FETCH state until it cancels the request (see Section 3.3.3), receives REQUEST_ERROR, or the FETCH data stream receives a FIN or is reset. If the data stream is already open, the subscriber wishing to cancel the FETCH MAY send STOP_SENDING for the data stream as well as the bidi request stream. It MUST send STOP_SENDING for the bidi request stream.
The Publisher can destroy fetch state as soon as it has received a STOP_SENDING. It MUST reset the bidi request stream and unidirectional data stream associated with the FETCH. It can also destroy state after closing the FETCH data stream.
It can destroy all FETCH state after closing the data stream with a FIN.
A REQUEST_ERROR indicates that both endpoints can immediately destroy state. Since a relay can start delivering FETCH Objects from cache before determining the result of the request, some Objects could be received even if the FETCH results in error.