diff --git a/src/Network/Wai/EventSource.hs b/src/Network/Wai/EventSource.hs
--- a/src/Network/Wai/EventSource.hs
+++ b/src/Network/Wai/EventSource.hs
@@ -23,10 +23,13 @@
 res :: Chan ServerEvent -> Response
 res chan = ResponseSource statusOK [("Content-Type", "text/event-stream")] $ resE chan
 
-resE :: Chan ServerEvent -> C.Source IO Builder
+resE :: Chan ServerEvent -> C.Source IO (C.Flush Builder)
 resE chan =
-  C.sourceIO ign (const ign) (const $ fmap (f . eventToBuilder) $ readChan chan)
+    C.sourceState Nothing pull
   where
-    ign = return ()
-    f Nothing = C.Closed
-    f (Just b) = C.Open b
+    pull Nothing = do
+        x <- liftIO $ readChan chan
+        return $ case eventToBuilder x of
+            Nothing -> C.StateClosed
+            Just y -> C.StateOpen (Just C.Flush) (C.Chunk y)
+    pull (Just x) = return $ C.StateOpen Nothing x
diff --git a/wai-eventsource.cabal b/wai-eventsource.cabal
--- a/wai-eventsource.cabal
+++ b/wai-eventsource.cabal
@@ -1,5 +1,5 @@
 Name:                wai-eventsource
-Version:             1.0.0
+Version:             1.1.0
 Synopsis:            WAI support for server-sent events
 Description:         WAI support for server-sent events
 License:             BSD3
@@ -17,10 +17,10 @@
       base                      >= 4.3 && < 5
     , bytestring                >= 0.9.1.4  && < 0.10
     , blaze-builder             >= 0.3 && < 0.4
-    , conduit
+    , conduit                   >= 0.2
     , http-types                >= 0.6      && < 0.7
-    , wai                       >= 1.0
-    , warp                      >= 1.0
+    , wai                       >= 1.1
+    , warp                      >= 1.1
     , transformers
 
   ghc-options:     -Wall