diff --git a/src/emqx_channel.erl b/src/emqx_channel.erl
index aa9a9f897..9c908c9bf 100644
--- a/src/emqx_channel.erl
+++ b/src/emqx_channel.erl
@@ -259,8 +259,7 @@ connected(enter, _PrevSt, State = #state{proto_state = ProtoState}) ->
     %% Ensure keepalive after connected successfully.
     Interval = emqx_protocol:info(keepalive, ProtoState),
     case ensure_keepalive(Interval, NState) of
-        ignore ->
-            keep_state(NState);
+        ignore -> keep_state(NState);
         {ok, KeepAlive} ->
             keep_state(NState#state{keepalive = KeepAlive});
         {error, Reason} ->
diff --git a/src/emqx_ws_channel.erl b/src/emqx_ws_channel.erl
index 3c04e4cea..1c21c29d8 100644
--- a/src/emqx_ws_channel.erl
+++ b/src/emqx_ws_channel.erl
@@ -270,7 +270,7 @@ websocket_info(Deliver = {deliver, _Topic, _Msg},
         {ok, NProtoState} ->
             reply(State#state{proto_state = NProtoState});
         {ok, Packets, NProtoState} ->
-            reply(Packets, State#state{proto_state = NProtoState});
+            reply(enqueue(Packets, State#state{proto_state = NProtoState}));
         {error, Reason} ->
             stop(Reason, State);
         {error, Reason, NProtoState} ->
@@ -282,7 +282,6 @@ websocket_info({keepalive, check}, State = #state{keepalive = KeepAlive}) ->
         {ok, KeepAlive1} ->
             {ok, State#state{keepalive = KeepAlive1}};
         {error, timeout} ->
-            ?LOG(debug, "Keepalive Timeout!"),
             stop(keepalive_timeout, State);
         {error, Error} ->
             ?LOG(error, "Keepalive error: ~p", [Error]),
@@ -315,7 +314,7 @@ websocket_info({timeout, Timer, Msg},
         {ok, NProtoState} ->
             {ok, State#state{proto_state = NProtoState}};
         {ok, Packets, NProtoState} ->
-            reply(Packets, State#state{proto_state = NProtoState});
+            reply(enqueue(Packets, State#state{proto_state = NProtoState}));
         {error, Reason} ->
             stop(Reason, State);
         {error, Reason, NProtoState} ->
@@ -364,8 +363,7 @@ connected(State = #state{proto_state = ProtoState}) ->
     %% Ensure keepalive after connected successfully.
     Interval = emqx_protocol:info(keepalive, ProtoState),
     case ensure_keepalive(Interval, NState) of
-        ignore ->
-            reply(NState);
+        ignore -> reply(NState);
         {ok, KeepAlive} ->
             reply(NState#state{keepalive = KeepAlive});
         {error, Reason} ->
@@ -377,16 +375,10 @@ connected(State = #state{proto_state = ProtoState}) ->
 
 ensure_keepalive(0, _State) ->
     ignore;
-ensure_keepalive(Interval, State = #state{proto_state = ProtoState}) ->
+ensure_keepalive(Interval, #state{proto_state = ProtoState}) ->
     Backoff = emqx_zone:get_env(emqx_protocol:info(zone, ProtoState),
                                 keepalive_backoff, 0.75),
-    case emqx_keepalive:start(stat_fun(), round(Interval * Backoff), {keepalive, check}) of
-        {ok, KeepAlive} ->
-            {ok, State#state{keepalive = KeepAlive}};
-        {error, Reason} ->
-            ?LOG(warning, "Keepalive error: ~p", [Reason]),
-            stop(Reason, State)
-    end.
+    emqx_keepalive:start(stat_fun(), round(Interval * Backoff), {keepalive, check}).
 
 %%--------------------------------------------------------------------
 %% Process incoming data
@@ -415,8 +407,7 @@ process_incoming(Data, State = #state{parse_state = ParseState}) ->
 %% Handle incoming packets
 
 handle_incoming(Packet = ?PACKET(Type), SuccFun,
-                State = #state{proto_state = ProtoState,
-                               pendings = Pendings}) ->
+                State = #state{proto_state = ProtoState}) ->
     _ = inc_incoming_stats(Type),
     ok = emqx_metrics:inc_recv(Packet),
     ?LOG(debug, "RECV ~s", [emqx_packet:format(Packet)]),
@@ -424,9 +415,7 @@ handle_incoming(Packet = ?PACKET(Type), SuccFun,
         {ok, NProtoState} ->
             SuccFun(State#state{proto_state = NProtoState});
         {ok, OutPackets, NProtoState} ->
-            Pendings1 = lists:append(Pendings, OutPackets),
-            SuccFun(State#state{proto_state = NProtoState,
-                                pendings = Pendings1});
+            SuccFun(enqueue(OutPackets, State#state{proto_state = NProtoState}));
         {error, Reason, NProtoState} ->
             stop(Reason, State#state{proto_state = NProtoState});
         {stop, Error, NProtoState} ->
@@ -436,9 +425,6 @@ handle_incoming(Packet = ?PACKET(Type), SuccFun,
 %%--------------------------------------------------------------------
 %% Handle outgoing packets
 
-handle_outgoing(Packet, State) when is_tuple(Packet) ->
-    handle_outgoing([Packet], State);
-
 handle_outgoing(Packets, #state{serialize = Serialize}) ->
     Data = lists:map(Serialize, Packets),
     emqx_pd:update_counter(send_oct, iolist_size(Data)),
@@ -471,10 +457,6 @@ inc_outgoing_stats(Type) ->
 %%--------------------------------------------------------------------
 %% Reply or Stop
 
-reply(Packets, State = #state{pendings = Pendings}) ->
-    Pendings1 = lists:append(Pendings, Packets),
-    reply(State#state{pendings = Pendings1}).
-
 reply(State = #state{pendings = []}) ->
     {ok, State};
 reply(State = #state{pendings = Pendings}) ->
@@ -488,6 +470,11 @@ stop(Reason, State = #state{pendings = Pendings}) ->
     {reply, [Reply, close],
      State#state{pendings = [], reason = Reason}}.
 
+enqueue(Packet, State) when is_record(Packet, mqtt_packet) ->
+    enqueue([Packet], State);
+enqueue(Packets, State = #state{pendings = Pendings}) ->
+    State#state{pendings = lists:append(Pendings, Packets)}.
+
 %%--------------------------------------------------------------------
 %% Ensure stats timer