chore(update): add hot update version 5.7.4

Author: wwhai

Diff for: src/esockd.appup.src

@@ -1,6 +1,10 @@
 %%-*-: erlang -*-
 
-{"5.7.3",
- [{"5.7.2", [{load_module, esockd_transport, brutal_purge, soft_purge, []}]}],
- [{"5.7.2", [{load_module, esockd_transport, brutal_purge, soft_purge, []}]}]
+{"5.7.4",
+ [{"5.7.3", [{load_module, esockd_udp, brutal_purge, soft_purge, []}]},
+  {"5.7.2", [{load_module, esockd_udp, brutal_purge, soft_purge, []},
+             {load_module, esockd_transport, brutal_purge, soft_purge, []}]}],
+ [{"5.7.3", [{load_module, esockd_udp, brutal_purge, soft_purge, []}]},
+  {"5.7.2", [{load_module, esockd_udp, brutal_purge, soft_purge, []},
+             {load_module, esockd_transport, brutal_purge, soft_purge, []}]}]
 }.

Diff for: src/esockd_udp.erl

@@ -273,18 +273,10 @@ handle_info({timeout, TRef, activate_sock}, State = #state{limit_timer = TRef})
     {noreply, activate_sock(NState)};
 
 handle_info({'DOWN', _MRef, process, DownPid, _Reason}, State = #state{peers = Peers}) ->
-    case maps:find(DownPid, Peers) of
-        {ok, Peer} ->
-            {noreply, erase_peer(Peer, DownPid, State)};
-        error -> {noreply, State}
-    end;
+    handle_peer_down(DownPid, Peers, State);
 
 handle_info({'EXIT', DownPid, _Reason}, State = #state{peers = Peers}) ->
-    case maps:find(DownPid, Peers) of
-        {ok, Peer} ->
-            {noreply, erase_peer(Peer, DownPid, State)};
-        error -> {noreply, State}
-    end;
+    handle_peer_down(DownPid, Peers, State);
 
 handle_info({datagram, Peer = {IP, Port}, Packet}, State = #state{sock = Sock}) ->
     case gen_udp:send(Sock, IP, Port, Packet) of
@@ -293,7 +285,6 @@ handle_info({datagram, Peer = {IP, Port}, Packet}, State = #state{sock = Sock})
             ?ERROR_MSG("Dropped packet to: ~s, reason: ~s", [esockd:format(Peer), Reason])
     end,
     {noreply, State};
-
 handle_info(Info, State) ->
     ?ERROR_MSG("Unexpected info: ~p", [Info]),
     {noreply, State}.
@@ -308,6 +299,14 @@ code_change(_OldVsn, State, _Extra) ->
 %% Internel functions
 %%--------------------------------------------------------------------
 
+handle_peer_down(DownPid, Peers, State) ->
+    case maps:find(DownPid, Peers) of
+        {ok, Peer} ->
+            {noreply, erase_peer(Peer, DownPid, State)};
+        error ->
+            {noreply, State}
+    end.
+
 -compile({inline,
           [ allowed/2
           , should_throttle/1