I need the most efficient C# RSS reader possible

I am developing an app that will monitor several thousands of feeds from across the web.

I have a simple RSS reader that will do the trick, but I am worried about bandwidth and latency issues - this must be as fast and efficient as possible.

I want an RSS reader/library that polls a feed and checks if it has updated without downloading any content (by analyzing the date header in the开发者_运维知识库 response, for example), and using local caching to reduce bandwidth so the entire feed is never re-downloaded.

My important metrics are minimum bandwidth and minimum access latency. I don't care about memory usage, disk space, processing power etc.

Is there any library out there that does all this automatically?

---

Jeff says, do it yourself.