diff --git a/hstream-kafka/HStream/Kafka/Network.hs b/hstream-kafka/HStream/Kafka/Network.hs
index 106407b1b..ddfe1f90e 100644
--- a/hstream-kafka/HStream/Kafka/Network.hs
+++ b/hstream-kafka/HStream/Kafka/Network.hs
@@ -143,7 +143,7 @@ runHsServer opts sc_ mkPreAuthedHandlers mkAuthedHandlers =
 
     doUnaryHandler l reqHeader@RequestHeader{..} rpcHandler' peer = do
       (req, left) <- runGet' l
-      when (not . BS.null $ left) $
+      unless (BS.null left) $
         Log.warning $ "Leftover bytes: " <> Log.buildString' left
       Log.debug $ "Received request "
                <> Log.buildString' requestApiKey
@@ -237,10 +237,14 @@ runCppServer opts sc_ mkAuthedHandlers =
         (sc, conn) <- deRefStablePtr sptr
         let handlers = mkAuthedHandlers sc
         req <- peek request_ptr
+        M.incCounter M.totalRequests
+        (header, reqBs) <- runGet' @RequestHeader req.requestPayload
+        let ServiceHandler{..} = findHandler handlers header.requestApiKey header.requestApiVersion
         -- respBs: Nothing means some error occurred, and the server will close
         -- the connection
         respBs <- E.catch
-          (Just <$> handleKafkaMsg conn handlers req.requestPayload)
+          (Just <$> M.observeWithLabel M.handlerLatencies (Text.pack $ show header.requestApiKey)
+                    (handleKafkaMsg conn rpcHandler header reqBs))
           (\err -> do Log.fatal $ Log.buildString' (err :: E.SomeException)
                       pure Nothing)
         poke response_ptr Cxx.Response{responseData = respBs}
@@ -250,19 +254,21 @@ runCppServer opts sc_ mkAuthedHandlers =
 -- Server misc
 
 handleKafkaMsg
-  :: Cxx.ConnContext -> [ServiceHandler] -> ByteString -> IO ByteString
-handleKafkaMsg conn handlers bs = do
-  (header, reqBs) <- runGet' @RequestHeader bs
-  let ServiceHandler{..} = findHandler handlers header.requestApiKey header.requestApiVersion
+  :: Cxx.ConnContext
+  -> RpcHandler
+  -> RequestHeader
+  -> ByteString
+  -> IO ByteString
+handleKafkaMsg conn rpcHandler header bs = do
   case rpcHandler of
     UnaryHandler rpcHandler' -> do
-      (req, left) <- runGet' reqBs
+      (req, left) <- runGet' bs
       Log.debug $ "Received request "
                <> Log.buildString' header.requestApiKey
                <> ":v" <> Log.build header.requestApiVersion
                <> " from " <> Log.buildString' conn.peerHost
                <> ", payload: " <> Log.buildString' req
-      when (not . BS.null $ left) $
+      unless (BS.null left) $
         Log.warning $ "Leftover bytes: " <> Log.buildString' left
       let reqContext =
             RequestContext