Add data using a feed/parser function.

        Args:
            name (str): The name of the feed record format.
            items (list): A list of items to ingest.
            seqn ((str,int)): An (iden, offs) tuple for this feed chunk.

        Returns:
            (int): The next expected offset (or None) if seqn is None.

async def addFeedData(self, name, items, seqn=None):
        '''
        Add data using a feed/parser function.

        Args:
            name (str): The name of the feed record format.
            items (list): A list of items to ingest.
            seqn ((str,int)): An (iden, offs) tuple for this feed chunk.

        Returns:
            (int): The next expected offset (or None) if seqn is None.
        '''
        async with await self.snap() as snap:
            snap.strict = False
            return await snap.addFeedData(name, items, seqn=seqn)