diff --git a/Network/Wai/Enumerator.hs b/Network/Wai/Enumerator.hs
--- a/Network/Wai/Enumerator.hs
+++ b/Network/Wai/Enumerator.hs
@@ -15,6 +15,8 @@
       -- ** FilePath
     , fromFile
     , fromEitherFile
+      -- * Filters
+    , buffer
     ) where
 
 import Network.Wai (Enumerator (..), Source (..))
@@ -67,16 +69,16 @@
 -- deadlocked.
 toSource :: Enumerator -> IO Source
 toSource (Enumerator e) = do
-    buffer <- newEmptyMVar
-    _ <- forkIO $ e (helper buffer) () >> putMVar buffer Nothing
-    return $ source buffer
+    buff <- newEmptyMVar
+    _ <- forkIO $ e (helper buff) () >> putMVar buff Nothing
+    return $ source buff
       where
         helper :: MVar (Maybe B.ByteString)
                -> ()
                -> B.ByteString
                -> IO (Either () ())
-        helper buffer _ bs = do
-            putMVar buffer $ Just bs
+        helper buff _ bs = do
+            putMVar buff $ Just bs
             return $ Right ()
         source :: MVar (Maybe B.ByteString)
                -> Source
@@ -115,3 +117,24 @@
 -- be convenient for server implementations not optimizing file sending.
 fromEitherFile :: Either FilePath Enumerator -> Enumerator
 fromEitherFile = either fromFile id
+
+-- | Buffer chunks until we have a chunk of 'defaultChunkSize', and then send
+-- it.
+buffer :: Enumerator -> Enumerator
+buffer (Enumerator e) =
+    Enumerator go
+  where
+    go iter seed = do
+        res <- e (iter' iter) (B.empty, seed)
+        case res of
+            Left (_, seed') -> return $ Left seed'
+            Right (buff, seed') -> iter seed' buff
+    iter' iter (buff, seed) bs = do
+        if B.length buff + B.length bs < defaultChunkSize
+            then return $ Right (buff `B.append` bs, seed)
+            else do
+                let (x, y) = B.splitAt (defaultChunkSize - B.length buff) bs
+                res <- iter seed $ buff `B.append` x
+                case res of
+                    Left seed' -> return $ Left (y, seed') -- y is ignored
+                    Right seed' -> return $ Right (y, seed')
diff --git a/wai.cabal b/wai.cabal
--- a/wai.cabal
+++ b/wai.cabal
@@ -1,5 +1,5 @@
 Name:                wai
-Version:             0.0.0
+Version:             0.0.1
 Synopsis:            Web Application Interface.
 Description:         Provides a common protocol for communication between web aplications and web servers.
 License:             BSD3
@@ -9,8 +9,12 @@
 Homepage:            http://github.com/snoyberg/wai
 Category:            Web
 Build-Type:          Simple
-Cabal-Version:       >=1.2
+Cabal-Version:       >=1.6
 Stability:           Stable
+
+Source-repository head
+    type:            git
+    location:        git://github.com/snoyberg/wai.git
 
 Library
   Build-Depends:     base >= 3 && < 5,