Increase TCP listen connection backlog, for parity with prospect TCP driver

plain-racket-server.rkt

@@ -62,7 +62,7 @@
 	  (loop)])))))
 
 (define (listener port-number)
-  (define s (tcp-listen port-number 4 #t))
+  (define s (tcp-listen port-number 128 #t))
   (let loop ()
     (define-values (in out) (tcp-accept s))
     (connection in out)