diff --git a/src/emqx_connection.erl b/src/emqx_connection.erl
index ccb5f59fa..37665ac10 100644
--- a/src/emqx_connection.erl
+++ b/src/emqx_connection.erl
@@ -165,7 +165,8 @@ init_limiter({Rate, Burst}) ->
     esockd_rate_limit:new(Rate, Burst).
 
 send_fun(Transport, Socket, Peername) ->
-    fun(Data) ->
+    fun(Serialize, Packet, Options) ->
+        Data = Serialize(Packet, Options),
         try Transport:async_send(Socket, Data) of
             ok ->
                 ?LOG(debug, "SEND ~p", [iolist_to_binary(Data)], #state{peername = Peername}),
@@ -408,4 +409,3 @@ maybe_gc(#state{}, {publish, _PacketId, #message{payload = Payload}}) ->
     ok = emqx_gc:inc(1, Oct);
 maybe_gc(_, _) ->
     ok.
-
diff --git a/src/emqx_frame.erl b/src/emqx_frame.erl
index aa7aad064..075f0a11e 100644
--- a/src/emqx_frame.erl
+++ b/src/emqx_frame.erl
@@ -130,7 +130,7 @@ parse_packet(#mqtt_packet_header{type = ?CONNECT}, FrameBin, _Options) ->
       WillQoS      : 2,
       WillFlag     : 1,
       CleanStart   : 1,
-      0            : 1,         
+      0            : 1,
       KeepAlive    : 16/big,
       Rest2/binary>> = Rest1,
 
@@ -634,4 +634,3 @@ fixqos(?PUBREL, 0)      -> 1;
 fixqos(?SUBSCRIBE, 0)   -> 1;
 fixqos(?UNSUBSCRIBE, 0) -> 1;
 fixqos(_Type, QoS)      -> QoS.
-
diff --git a/src/emqx_protocol.erl b/src/emqx_protocol.erl
index 1fb80c0ce..93a1a8b64 100644
--- a/src/emqx_protocol.erl
+++ b/src/emqx_protocol.erl
@@ -407,13 +407,13 @@ process_packet(?UNSUBSCRIBE_PACKET(PacketId, Properties, RawTopicFilters),
 process_packet(?PACKET(?PINGREQ), PState) ->
     send(?PACKET(?PINGRESP), PState);
 
-process_packet(?DISCONNECT_PACKET(?RC_SUCCESS, #{'Session-Expiry-Interval' := Interval}), 
+process_packet(?DISCONNECT_PACKET(?RC_SUCCESS, #{'Session-Expiry-Interval' := Interval}),
                 PState = #pstate{session = SPid, conn_props = #{'Session-Expiry-Interval' := OldInterval}}) ->
     case Interval =/= 0 andalso OldInterval =:= 0 of
-        true -> 
+        true ->
             deliver({disconnect, ?RC_PROTOCOL_ERROR}, PState),
             {error, protocol_error, PState#pstate{will_msg = undefined}};
-        false -> 
+        false ->
             emqx_session:update_expiry_interval(SPid, Interval),
             %% Clean willmsg
             {stop, normal, PState#pstate{will_msg = undefined}}
@@ -495,13 +495,13 @@ deliver({connack, ?RC_SUCCESS, SP}, PState = #pstate{zone = Zone,
               'Subscription-Identifier-Available' => 1,
               'Shared-Subscription-Available' => flag(Shared)},
 
-    Props1 = if 
-                MaxQoS =:= ?QOS_2 -> 
+    Props1 = if
+                MaxQoS =:= ?QOS_2 ->
                     Props;
                 true ->
                     maps:put('Maximum-QoS', MaxQoS, Props)
             end,
-    
+
     Props2 = if IsAssigned ->
                     Props1#{'Assigned-Client-Identifier' => ClientId};
                 true -> Props1
@@ -555,7 +555,7 @@ deliver({disconnect, _ReasonCode}, PState) ->
 -spec(send(emqx_mqtt_types:packet(), state()) -> {ok, state()} | {error, term()}).
 send(Packet = ?PACKET(Type), PState = #pstate{proto_ver = Ver, sendfun = SendFun}) ->
     trace(send, Packet, PState),
-    case SendFun(emqx_frame:serialize(Packet, #{version => Ver})) of
+    case SendFun(fun emqx_frame:serialize/2, Packet, #{version => Ver}) of
         ok ->
             emqx_metrics:sent(Packet),
             {ok, inc_stats(send, Type, PState)};
@@ -601,17 +601,17 @@ set_session_attrs({max_inflight, #pstate{zone = Zone, proto_ver = ProtoVer, conn
     maps:put(max_inflight, if
                                ProtoVer =:= ?MQTT_PROTO_V5 ->
                                    maps:get('Receive-Maximum', ConnProps, 65535);
-                               true -> 
+                               true ->
                                    emqx_zone:get_env(Zone, max_inflight, 65535)
                            end, SessAttrs);
 set_session_attrs({expiry_interval, #pstate{zone = Zone, proto_ver = ProtoVer, conn_props = ConnProps, clean_start = CleanStart}}, SessAttrs) ->
     maps:put(expiry_interval, if
                                ProtoVer =:= ?MQTT_PROTO_V5 ->
                                    maps:get('Session-Expiry-Interval', ConnProps, 0);
-                               true -> 
+                               true ->
                                    case CleanStart of
                                        true -> 0;
-                                       false -> 
+                                       false ->
                                            emqx_zone:get_env(Zone, session_expiry_interval, 16#ffffffff)
                                    end
                            end, SessAttrs);
@@ -619,7 +619,7 @@ set_session_attrs({topic_alias_maximum, #pstate{zone = Zone, proto_ver = ProtoVe
     maps:put(topic_alias_maximum, if
                                     ProtoVer =:= ?MQTT_PROTO_V5 ->
                                         maps:get('Topic-Alias-Maximum', ConnProps, 0);
-                                    true -> 
+                                    true ->
                                         emqx_zone:get_env(Zone, max_topic_alias, 0)
                                   end, SessAttrs);
 set_session_attrs({_, #pstate{}}, SessAttrs) ->
diff --git a/src/emqx_ws_connection.erl b/src/emqx_ws_connection.erl
index fa08fa1bb..1907695af 100644
--- a/src/emqx_ws_connection.erl
+++ b/src/emqx_ws_connection.erl
@@ -144,7 +144,8 @@ websocket_init(#state{request = Req, options = Options}) ->
                 idle_timeout = IdleTimout}}.
 
 send_fun(WsPid) ->
-    fun(Data) ->
+    fun(Serialize, Packet, Options) ->
+        Data = Serialize(Packet, Options),
         BinSize = iolist_size(Data),
         emqx_metrics:inc('bytes/sent', BinSize),
         put(send_oct, get(send_oct) + BinSize),
@@ -299,4 +300,3 @@ stop(Error, State) ->
 
 wsock_stats() ->
     [{Key, get(Key)} || Key <- ?SOCK_STATS].
-