diff --git a/collects/web-server/http/response.ss b/collects/web-server/http/response.ss
index 786a0c3ec9..67de979f97 100644
--- a/collects/web-server/http/response.ss
+++ b/collects/web-server/http/response.ss
@@ -110,10 +110,13 @@
          (begin
            ((response/incremental-generator bresp)
             (lambda chunks
-              (fprintf o-port "~x\r\n"
-                       (apply + 0 (map bytes-length chunks)))                     
-              (for-each (lambda (chunk) (display chunk o-port)) chunks)
-              (fprintf o-port "\r\n")))
+              (define length (apply + 0 (map bytes-length chunks)))
+              (if (zero? length)
+                  (flush-output o-port)
+                  (begin
+                    (fprintf o-port "~x\r\n" length)                  
+                    (for-each (lambda (chunk) (display chunk o-port)) chunks)
+                    (fprintf o-port "\r\n")))))
            ; one \r\n ends the last (empty) chunk and the second \r\n ends the (non-existant) trailers
            (fprintf o-port "0\r\n\r\n")))]))
 
diff --git a/collects/web-server/scribblings/http.scrbl b/collects/web-server/scribblings/http.scrbl
index ba62a74bfc..af5d2730bb 100644
--- a/collects/web-server/scribblings/http.scrbl
+++ b/collects/web-server/scribblings/http.scrbl
@@ -199,7 +199,9 @@ Here is an example typical of what you will find in many applications:
            ([generator ((() () #:rest (listof bytes?) . ->* . any) . -> . any)])]{
  As with @scheme[response/basic], except with @scheme[generator] as a function that is
  called to generate the response body, by being given an @scheme[output-response] function
- that outputs the content it is called with.
+ that outputs the content it is called with. If the @scheme[output-response] function is called
+ with arguments of zero length (when concatenated), then the output port is flushed with
+ @scheme[flush-output].
  
  Here is a short example:
  @schemeblock[
@@ -208,11 +210,11 @@ Here is an example typical of what you will find in many applications:
     #"application/octet-stream"
     (list (make-header #"Content-Disposition"
                        #"attachment; filename=\"file\""))
-    (lambda (send/bytes)
-      (send/bytes #"Some content")
-      (send/bytes)
-      (send/bytes #"Even" #"more" #"content!")
-      (send/bytes #"Now we're done")))
+    (lambda (output-response)
+      (output-response #"Some content")
+      (output-response)
+      (output-response #"Even" #"more" #"content!")
+      (output-response #"Now we're done")))
  ]
 }