Request-reply worker in Racket

#lang racket
#|
Request-reply server in Racket
Binds REP socket to tcp://*:5560
Expects "Hello" from client, replies with "World"
|#
(require net/zmq)

(define ctxt (context 1))
(define sock (socket ctxt 'REP))
(socket-bind! sock "tcp://*:5560")

(let loop ()
(define message (socket-recv! sock))
(printf "Received request: ~a\n" message)
(sleep 1)
(socket-send! sock #"World")
(loop))

(context-close! ctxt)