C# command line app - make http requests parallel and fast - repost

I need a small command line app that will let me put in a url to a resource (like a .gif) it will then make a lot of requests for that gif. I should be able to input parallel thread count. Command should show some progress on the requests, like speed or time for response. (i need this very accurate, milliseconds matter here a lot) We are using this to target a specific type of load on our web apps for a specific type of resource. .net 4.5 is fine and needs to run on windows 8 machine