better type signature for client's aux

Network/HTTP2/Client/Run.hs

@@ -54,14 +54,15 @@ run cconf@ClientConfig{..} conf client = do
     (ctx, mgr) <- setup cconf conf
     runH2 conf ctx mgr $ runClient ctx mgr
   where
-    serverMaxStreams ctx = maxConcurrentStreams <$> readIORef (peerSettings ctx)
-    possibleClientStream ctx = do
-        mx <- serverMaxStreams ctx
+    serverMaxStreams ctx = do
+        mx <- maxConcurrentStreams <$> readIORef (peerSettings ctx)
         case mx of
-            Nothing -> return Nothing
-            Just x -> do
-                n <- oddConc <$> readTVarIO (oddStreamTable ctx)
-                return $ Just (x - n)
+          Nothing -> return maxBound
+          Just x  -> return x
+    possibleClientStream ctx = do
+        x <- serverMaxStreams ctx
+        n <- oddConc <$> readTVarIO (oddStreamTable ctx)
+        return (x - n)
     aux ctx =
         Aux
             { auxPossibleClientStreams = possibleClientStream ctx

Network/HTTP2/Client/Types.hs

@@ -17,10 +17,10 @@ newtype Response = Response InpObj deriving (Show)
 
 -- | Additional information.
 data Aux = Aux
-    { auxPossibleClientStreams :: IO (Maybe Int)
+    { auxPossibleClientStreams :: IO Int
     -- ^ How many streams can be created without blocking.
-    -- 'Nothing' means infinity.
-    , auxServerMaxStreams :: IO (Maybe Int)
+    , auxServerMaxStreams :: IO Int
     -- ^ Getting server's SETTINGS_MAX_CONCURRENT_STREAMS.
-    --  'Nothing' means no limit.
+    --   If the server does not inform it,
+    --   'concurrentStreams' is used.
     }