private static MultipartFormDataOutput create(final List<EntityPart> entityParts) {
    final MultipartFormDataOutput output = new MultipartFormDataOutput();
    for (EntityPart entityPart : entityParts) {
        final OutputPart part = output.addFormData(entityPart.getName(), entityPart.getContent(), entityPart.getMediaType(),
                entityPart.getFileName()
                        .orElse(null));
        entityPart.getHeaders().forEach((name, value) -> part.getHeaders().addAll(name, value));
    }
    return output;
}