Allowed memory size errors

So it appears ZipStream isn't really doing anything to help stream the zip file and enable large downloads. When being used it continually gets "Allowed memory size..." fatal errors. Not sure what I am doing wrong with this class, it used to work quite well. The old version and now v2 both have the same problem.

This issue appears on several shared hosts running at least 5.3 with mbstring.func_overload disabled