(use gauche.net)
;; borrowed from tests/mail.scm
(with-module 
 gauche.net
 (define (smtp-responses)
   (string-join (map number->string 
                     (list 220 250 250 250 354 250 221 ))
                "\n"))

 (define (call-with-client-socket socket proc)
   (call-with-input-string (smtp-responses)
                           (lambda (smtp-port)
                             (proc smtp-port
                                   (standard-output-port)))))

 (define (make-client-socket type host port)
   'dummy))