Prepare to switch to the unit-based resolver in the proxy

proxy.rkt

@@ -2,6 +2,7 @@
 
 ;; Simple imperative DNS proxy.
 
+(require racket/unit)
 (require racket/match)
 (require racket/udp)
 (require racket/set)
@@ -10,11 +11,14 @@
 (require "api.rkt")
 (require "codec.rkt")
 (require "zonedb.rkt")
+(require "resolver-unit.rkt")
 (require "dump-bytes.rkt")
 (require "simple-udp-service.rkt")
 
 (require racket/pretty)
 
+(define-values/invoke-unit/infer (link resolver@ simple-udp-service-udp-operations@))
+
 ;; Instantiated with a collection of trusted roots to begin its
 ;; searches from. Performs recursive queries. Doesn't yet cache
 ;; responses, but will do so in future.