RoR alternative to mod_deflate

Hey Everyone,
I’m experiencing the following general problem. I have a single instance of mongrel on a shared hosting environment. I’m just a hobbyist so I don’t want to have to spend too much on hosting. Some of the files I’m serving through rails, noteably, the sitemap.xml, are relatively large. (I also realize I should be serving that directly from apache, but thats not the point =) It is my understanding that my one mongrel instance will be consumed while the actual bytes of the served file are being sent over the wire, correct? In order to cut down on this time, I would like to use mod_deflate (or a similar technology). My hosting providor doesn’t support mod_deflate. Does anyone know of a ruby on rails plugin that can compress my outgoing files? Or is this a problem that I shouldn’t need to worry about because I’m misunderstanding how mongrel servers works.