private static SequencePosition ReadItems(in ReadOnlySequence<byte> sequence, bool isCompleted)
{
    var reader = new SequenceReader<byte>(sequence);

    while (!reader.End) // loop until we've read the entire sequence
    {
        if (reader.TryReadTo(out ReadOnlySpan<byte> itemBytes, Comma, advancePastDelimiter: true)) // we have an item to handle
        {
            var stringLine = Encoding.UTF8.GetString(itemBytes);
            Console.WriteLine(stringLine);
        }
        else if (isCompleted) // read last item which has no final delimiter
        {
            var stringLine = ReadLastItem(sequence.Slice(reader.Position));
            Console.WriteLine(stringLine);
            reader.Advance(sequence.Length); // advance reader to the end
        }
        else // no more items in this sequence
        {
            break;
        }
    }

    return reader.Position;
}