@Override
    public int getApproxSize() {
        return 4 + 1; // type + priority // TODO update on Vespa 9 to not include deprecated fields
    }
Sets the priority tag for this message.

@param priority The priority to set.
@deprecated specifying explicit operation priority is deprecated
documentapi/src/main/java/com/yahoo/documentapi/messagebus/protocol/DocumentMessage.java