[plt-scheme] http authentication?

The net collection doesn't seem to have any support for basic HTTP
authentication, i.e. just plaintext username/password (rfc2617, I think).  I
didn't see anything likely on the Libraries and Extensions page, either.

Are there any libraries for PLT Scheme that support this?  All I want to do
is a simple retrieval of a file via a URL with basic authentication.

I realize there are many other ways to do this: shell out to wget, link in
some C code, use another scripting language, etc.  I'm trying to find out if
there's an existing way to do it within standard DrScheme, though.

Anton