private RestLiResponseAttachments(final RestLiResponseAttachments.Builder builder)
  {
    _multiPartMimeWriterBuilder = builder._multiPartMimeWriterBuilder;
  }
@Test
  public void testRestLiResponseAttachments()
  {
    //In this test we simply add a few attachments and verify the size of the resulting MultiPartMIMEWriter.
    //More detailed tests can be found in TestAttachmentUtils.

    final RestLiResponseAttachments emptyAttachments = new RestLiResponseAttachments.Builder().build();
    Assert.assertEquals(emptyAttachments.getMultiPartMimeWriterBuilder().getCurrentSize(), 0);

    //For multiple data attachments
    final RestLiTestAttachmentDataSource dataSourceA =
        new RestLiTestAttachmentDataSource("A", ByteString.copyString("partA", Charset.defaultCharset()));
    final RestLiTestAttachmentDataSource dataSourceB =
        new RestLiTestAttachmentDataSource("B", ByteString.copyString("partB", Charset.defaultCharset()));
    final RestLiTestAttachmentDataSource dataSourceC =
        new RestLiTestAttachmentDataSource("C", ByteString.copyString("partC", Charset.defaultCharset()));

    final RestLiResponseAttachments.Builder multipleAttachmentsBuilder = new RestLiResponseAttachments.Builder();
    multipleAttachmentsBuilder.appendSingleAttachment(dataSourceA);

    final RestLiTestAttachmentDataSourceIterator dataSourceIterator = new RestLiTestAttachmentDataSourceIterator(
        Arrays.asList(dataSourceB, dataSourceC), new IllegalArgumentException());
    multipleAttachmentsBuilder.appendMultipleAttachments(dataSourceIterator);

    RestLiResponseAttachments attachments = multipleAttachmentsBuilder.build();
    Assert.assertEquals(attachments.getMultiPartMimeWriterBuilder().getCurrentSize(), 2);
  }