Remove the use of masks

I don't think these are neccisary.
If an exception get's delivered at these points,
we couldn't do anything about it anyway

yesod-core/src/Yesod/Core/Internal/Run.hs

@@ -96,7 +96,7 @@ basicRunHandler :: ToTypedContent c
                 -> YesodRequest
                 -> InternalState
                 -> IO (GHState, HandlerContents)
-basicRunHandler rhe handler yreq resState = mask $ \unmask -> do
+basicRunHandler rhe handler yreq resState = do
     -- Create a mutable ref to hold the state. We use mutable refs so
     -- that the updates will survive runtime exceptions.
     istate <- I.newIORef defState
@@ -104,7 +104,7 @@ basicRunHandler rhe handler yreq resState = mask $ \unmask -> do
     -- Run the handler itself, capturing any runtime exceptions and
     -- converting them into a @HandlerContents@
     contents' <- unsafeAsyncCatch
-        (unmask $ do
+        (do
             res <- unHandlerFor handler (hd istate)
             tc <- evaluate (toTypedContent res)
             -- Success! Wrap it up in an @HCContent@
@@ -218,9 +218,9 @@ runHandler :: ToTypedContent c
            => RunHandlerEnv site site
            -> HandlerFor site c
            -> YesodApp
-runHandler rhe@RunHandlerEnv {..} handler yreq = withInternalState $ \resState -> mask $ \unmask -> do
+runHandler rhe@RunHandlerEnv {..} handler yreq = withInternalState $ \resState -> do
     -- Get the raw state and original contents
-    (state, contents0) <- unmask $ basicRunHandler rhe handler yreq resState
+    (state, contents0) <- basicRunHandler rhe handler yreq resState
 
     -- Evaluate the unfortunately-lazy session and headers,
     -- propagating exceptions into the contents