tcp-async-connection.rkt

(define (connect-to-server #:port [port 9393] #:hostname [hostname "127.0.0.1"])
  (define-values (conn-in conn-out) (tcp-connect hostname port))
  (define request-bindings (make-hash))
  (thread (thunk
	   (let loop ()
	     (define receive-evt (thread-receive-evt))
	     (match (sync conn-in receive-evt)
	       [(? (curry eq? receive-evt) th) 
		(match-define (job-request sexp return-channel) (thread-receive))
		(define id (random 4294967087))

		(write `(with-id ,id ,sexp) conn-out)
		(hash-set! request-bindings id return-channel)
		(flush-output conn-out)]

	       [(? input-port? in)
		(define res (read in))
		(match-define `(,id ,status ,result) res)
		(async-channel-put (hash-ref request-bindings id)
				   `(,status ,result))
		(hash-remove! request-bindings id)])
	     (loop)))))