private static Publisher<? extends BodyPart> partsPublisher(String boundary, List<byte[]> data,
                                                                AtomicLong totalCount) {
        final Publisher<HttpData> source = chunksPublisher(data, totalCount);
        return new MultipartDecoder(StreamMessage.of(source), boundary, ByteBufAllocator.DEFAULT);
    }
Create the parts publisher for the specified boundary and request chunks.
@param boundary multipart boundary string
@param data data for the chunks
@return publisher of body parts
core/src/test/java/com/linecorp/armeria/common/multipart/MultipartDecoderTest.java