关于formidable获取上传文件的tmp缓存文件

本人使用formidable上传文件,重写了"form.onPart = function(part) {}", github上说"You may overwrite this method if you are interested in directly accessing the multipart stream. Doing so will disable any 'field' / 'file' events processing which would occur otherwise, making you fully responsible for handling the processing."因此无法使用'field'/'file',请问有其他方式能获取得到吗?