[racket] Do I have a memory leak?

Hi,

I've been toying with a reactor loop that Greg Hendersonshott wrote a
while ago for tcp-connections.

I notice though that the memory start exploding when I starting
hitting it with apachebench.  So, I simplified the loop, to only
consume a very, very large file, and I have the same behavior

The code is here: https://gist.github.com/neomantic/7e687d75d9227ef16f81

I've tried manually garbage collecting, and all it did was slow the
loop, but the memory keeps growing.

Does anyone see anything obviously wrong with what I'm doing that
could be causing the memory of the process to keep growing and
growing?  I've even managed to get it to crash.

--
Chad Albers