nsurlsessiond is using all my bandwidth

I searched the web and apparently this process has something to do with the iCloud Drive! I don't have more than 10 MB for all the data and documents on iCloud Drive; but this process uses more than 300 MBs everytime it starts. It usually starts within a restart of the computer. I also checked the setting of iCloud drive on my iPhone and disabled all data backups and stuff for applications (even whatsapp and others which are not even on my mac). I have no idea what's causing this bandwidth hug. All photos cloud stuff has been turned off too. I don't use safari either; using chrome.

So what exactly is going on? Is the only way to fix this, turning off the whole iCloud Drive thing? Is this a bug? I'm using Yosemite 10.10

I like using iCloud drive to sync all Pages and Numbers documents between my iPhone and Mac (Which together are not more than 10 MBs).

The NSURLSession Daemon (nsurlsessiond) is used for uploading and downloading content. Apps can delegate transfers to the daemon which continues the transfer even after the delegating app quits.

So it could be any application. It's not restricted to Apple apps and services, all apps can use this daemon.