Like somehow you downloading Direwolf20 ep 40 map to find out that you are out in the no where and the console start saying end of ZLIB input stream. So, to solve this, let the launcher download a modpack and/or map MD5 hash, then download the modpack/map itself, and check the integrity. If the MD5 hash of the downloaded map/modpack doesn't match of the earlier MD5 hash, put out a big error message like this: WARNING download is corrupted!!!! Retry? Yes/No