[plt-scheme] anchor-case example

Could someone show an example of using the anchor-case macro in servlet-helpers.ss?

(require (lib "unitsig.ss")
         (lib "servlet-helpers.ss" "web-server")
         (lib "servlet-sig.ss" "web-server"))

(unit/sig ()
  (import servlet^)
   (anchor-case page
    ((anchor-pattern ...) ... body) ...))

Seems that no matter what I use for page and body, I get: reference to undefined
identifier: send/suspend.

I am also just generally confused about how to put this to use.  Will this do a
(send/suspend page) and the (send/suspend body) based on which anchor was
clicked in page?  So page and body should be k-urls?  Or should they call
send/suspend directly?

Thanks.
-d