此文件为下载模块，使用开源第三方库asihttprequest。可惜学习如何在ios上如何下载大文件数据以及断点下载。-This file is download the module, asihttprequest use open source third-party libraries. Unfortunately, learning how to ios on how to download large files, data and breakpoints download.

iPhone手机应用，实现文件下载的源码。只有源码文件，可以借鉴，参考！-iPhone mobile application file download source. Only the source code file, you can draw reference!