As you can see in the first part, the downloaded size is ‘4542’ that is not the actual size mentioned in here:
$ curl -I http://ftp.ir.debian.org/debian/pool/main/l/llvm-toolchain-3.5/libllvm3.5_3.5-10_amd64.deb
HTTP/1.1 200 OK
Date: Fri, 03 Jul 2015 05:38:35 GMT
Last-Modified: Fri, 27 Feb 2015 18:28:20 GMT
and the md5 hash of package is 0220e2e4a0ae74809350fd735af7571e in our mirror.
I think that there is no problem. Dear Muhammed, I advise you to attach the files in that situations for more [security] studies, we can not judge about that file now.
And please note that the ftp.ir.debian.org is up to date due the mirror monitoring page: http://mirror.debian.org/status.html