Reorganized login process...

...in order to improve stability and maintainability.

src/main/java/org/adde0109/ambassador/forge/FML2CRPMClientConnectionPhase.java

@@ -42,7 +42,7 @@ public class FML2CRPMClientConnectionPhase extends VelocityForgeClientConnection
     }
 
     MinecraftConnection connection = player.getConnection();
-    connection.setSessionHandler(new VelocityForgeHandshakeSessionHandler(connection.getSessionHandler(),this));
+    connection.setSessionHandler(new VelocityForgeHandshakeSessionHandler(connection.getSessionHandler(),player));
 
     ((VelocityServer) Ambassador.getInstance().server).unregisterConnection(player);
     this.clientPhase = null;
@@ -63,25 +63,7 @@ public class FML2CRPMClientConnectionPhase extends VelocityForgeClientConnection
     connection.write(new PluginMessage("fml:handshake",Unpooled.wrappedBuffer(ForgeHandshakeUtils.generatePluginResetPacket())));
     return future;
   }
-  public void complete(VelocityServer server, ConnectedPlayer player, MinecraftConnection connection) {
-    VelocityConfiguration configuration = (VelocityConfiguration) server.getConfiguration();
-    UUID playerUniqueId = player.getUniqueId();
-    if (configuration.getPlayerInfoForwardingMode() == PlayerInfoForwarding.NONE) {
-      playerUniqueId = UuidUtils.generateOfflinePlayerUuid(player.getUsername());
-    }
-    ServerLoginSuccess success = new ServerLoginSuccess();
-    success.setUsername(player.getUsername());
-    success.setUuid(playerUniqueId);
-    connection.write(success);
 
-    this.clientPhase = this.clientPhase == ClientPhase.MODLIST ? ClientPhase.MODDED : ClientPhase.VANILLA;
-
-    connection.setState(StateRegistry.PLAY);
-    connection.setSessionHandler(((VelocityForgeHandshakeSessionHandler) connection.getSessionHandler()).getOriginal());
-    ((VelocityServer) Ambassador.getInstance().server).registerConnection(player);
-
-    backupServer = null;
-  }
 
   public void handleKick(KickedFromServerEvent event) {
     if (backupServer != null && !(event.getResult() instanceof KickedFromServerEvent.RedirectPlayer)) {

src/main/java/org/adde0109/ambassador/forge/FML2ClientConnectionPhase.java

@@ -8,21 +8,24 @@ import com.velocitypowered.proxy.connection.backend.VelocityServerConnection;
 import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
 import com.velocitypowered.proxy.protocol.ProtocolUtils;
 import com.velocitypowered.proxy.protocol.packet.LoginPluginMessage;
+import com.velocitypowered.proxy.protocol.packet.LoginPluginResponse;
 import io.netty.buffer.ByteBuf;
 import net.kyori.adventure.text.Component;
 import org.adde0109.ambassador.Ambassador;
 import org.adde0109.ambassador.velocity.VelocityForgeClientConnectionPhase;
 
+import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.util.Arrays;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
 
 public class FML2ClientConnectionPhase extends VelocityForgeClientConnectionPhase {
 
   private Throwable throwable;
   private RegisteredServer triedServer;
-  private Continuation continuation;
+  private CompletableFuture<Void> onServerSuccess;
   private CompletableFuture<Void> onJoinGame;
 
   private static final Method CONNECT_TO_INITIAL_SERVER;
@@ -47,20 +50,9 @@ public class FML2ClientConnectionPhase extends VelocityForgeClientConnectionPhas
   }
 
   @Override
-  public void handleLogin(ConnectedPlayer player, VelocityServer server, Continuation continuation) {
-    this.continuation = continuation;
-    final MinecraftConnection connection = player.getConnection();
-
+  public RegisteredServer chooseServer(ConnectedPlayer player) {
     forced = Ambassador.getTemporaryForced().remove(player.getUsername());
-    if (forced != null) {
-      player.createConnectionRequest(forced).fireAndForget();
-    } else {
-      try {
-        CONNECT_TO_INITIAL_SERVER.invoke(player.getConnection().getSessionHandler(),player);
-      } catch (ReflectiveOperationException e) {
-        continuation.resumeWithException(e);
-      }
-    }
+    return forced;
   }
 
   @Override
@@ -77,17 +69,6 @@ public class FML2ClientConnectionPhase extends VelocityForgeClientConnectionPhas
     return future;
   }
 
-  @Override
-  public void complete(VelocityServer server, ConnectedPlayer player, MinecraftConnection connection) {
-    if (triedServer != null)
-      player.sendMessage(Component.translatable("velocity.error.connecting-server-error",
-              Component.text(triedServer.getServerInfo().getName())));
-    clientPhase = clientPhase == ClientPhase.MODLIST ? ClientPhase.MODDED : ClientPhase.VANILLA;
-    internalServerConnection = player.getConnectionInFlight();
-    player.resetInFlightConnection();
-    this.onJoinGame = new CompletableFuture<>();
-    continuation.resume();
-  }
 
   public void handleJoinGame() {
       this.onJoinGame.complete(null);

src/main/java/org/adde0109/ambassador/forge/ForgeConstants.java

@@ -7,6 +7,7 @@ public class ForgeConstants {
   public static final String MARKER_ADDER = "FML2/3 Marker Adder";
   public static final String OUTBOUND_CATCHER_NAME = "ambassador-catcher";
   public static final String RESET_LISTENER = "ambassador-reset-listener";
+  public static final String SERVER_SUCCESS_LISTENER = "ambassador-server-success-listener";
 
   public static final String FML2Marker = "\0FML2\0";
   public static final String FML3Marker = "\0FML3\0";

src/main/java/org/adde0109/ambassador/forge/ForgeFMLConnectionType.java

@@ -24,7 +24,7 @@ public class ForgeFMLConnectionType implements ConnectionType {
 
   @Override
   public BackendConnectionPhase getInitialBackendPhase() {
-    return new VelocityForgeBackendConnectionPhase();
+    return VelocityForgeBackendConnectionPhase.NOT_STARTED;
   }
 
   @Override

src/main/java/org/adde0109/ambassador/velocity/VelocityEventHandler.java

@@ -3,19 +3,15 @@ package org.adde0109.ambassador.velocity;
 import com.velocitypowered.api.event.Continuation;
 import com.velocitypowered.api.event.PostOrder;
 import com.velocitypowered.api.event.Subscribe;
+import com.velocitypowered.api.event.connection.LoginEvent;
 import com.velocitypowered.api.event.connection.PostLoginEvent;
-import com.velocitypowered.api.event.permission.PermissionsSetupEvent;
 import com.velocitypowered.api.event.player.*;
-import com.velocitypowered.proxy.VelocityServer;
+import com.velocitypowered.api.proxy.server.RegisteredServer;
 import com.velocitypowered.proxy.connection.backend.VelocityServerConnection;
 import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
-import com.velocitypowered.proxy.protocol.packet.ClientSettings;
+import com.velocitypowered.proxy.protocol.StateRegistry;
 import org.adde0109.ambassador.Ambassador;
 import org.adde0109.ambassador.forge.FML2CRPMClientConnectionPhase;
-import org.adde0109.ambassador.forge.FML2ClientConnectionPhase;
-import org.adde0109.ambassador.forge.ForgeConstants;
-import org.adde0109.ambassador.forge.ForgeFMLConnectionType;
-import org.adde0109.ambassador.velocity.backend.VelocityForgeBackendConnectionPhase;
 
 public class VelocityEventHandler {
 
@@ -26,16 +22,22 @@ public class VelocityEventHandler {
   }
 
   @Subscribe
-  public void onPermissionsSetupEvent(PermissionsSetupEvent event, Continuation continuation) {
-    if(!(event.getSubject() instanceof ConnectedPlayer player)) {
-      continuation.resume();
-      return;
+  public void onLoginEvent(LoginEvent event, Continuation continuation) {
+    ConnectedPlayer player = (ConnectedPlayer) event.getPlayer();
+    if (player.getPhase() instanceof VelocityForgeClientConnectionPhase) {
+      player.getConnection().eventLoop().submit(() -> player.getConnection().setState(StateRegistry.LOGIN));
     }
-    if (!(player.getPhase() instanceof VelocityForgeClientConnectionPhase phase)) {
-      continuation.resume();
-      return;
+    continuation.resume();
+  }
+
+  @Subscribe
+  public void onPostLoginEvent(PostLoginEvent event, Continuation continuation) {
+    ConnectedPlayer player = (ConnectedPlayer) event.getPlayer();
+    if (player.getPhase() instanceof VelocityForgeClientConnectionPhase phase) {
+      VelocityForgeHandshakeSessionHandler sessionHandler = new VelocityForgeHandshakeSessionHandler(player.getConnection().getSessionHandler(), player);
+      player.getConnection().eventLoop().submit(() -> player.getConnection().setSessionHandler(sessionHandler));
     }
-    player.getConnection().eventLoop().submit(() -> phase.fireLoginEvent(player, (VelocityServer) ambassador.server,continuation));
+    continuation.resume();
   }
 
   @Subscribe(order = PostOrder.LAST)
@@ -72,40 +74,10 @@ public class VelocityEventHandler {
       continuation.resume();
       return;
     }
-    if (event.getInitialServer().isEmpty())
-      event.setInitialServer(phase.internalServerConnection.getServer());
+    RegisteredServer chosenServer = phase.chooseServer(player);
+    if (chosenServer != null)
+      event.setInitialServer(chosenServer);
     continuation.resume();
   }
 
-  @Subscribe(order = PostOrder.LAST)
-  public void onServerPostConnectEvent(ServerPostConnectEvent event, Continuation continuation) {
-    ConnectedPlayer player = (ConnectedPlayer) event.getPlayer();
-    if (!(player.getPhase() instanceof VelocityForgeClientConnectionPhase phase)) {
-      continuation.resume();
-      return;
-    }
-    if (phase instanceof FML2ClientConnectionPhase specialPhase) {
-      specialPhase.handleJoinGame();
-    }
-    //if (((ConnectedPlayer) event.getPlayer()).getConnectedServer() != null && ((ConnectedPlayer) event.getPlayer()).getConnectedServer().getConnection() != null) {
-    //  ((ConnectedPlayer) event.getPlayer()).getConnectedServer().getConnection().write(new ClientSettings("en_GB", (byte) 10, 0, true, (short) 0xFF,1,false,true));
-    //}
-    continuation.resume();
-  }
-
-  @Subscribe
-  public void onLoginEvent(PostLoginEvent event, Continuation continuation) {
-    ConnectedPlayer player = (ConnectedPlayer) event.getPlayer();
-    if (!(player.getPhase() instanceof VelocityForgeClientConnectionPhase phase)) {
-      continuation.resume();
-      return;
-    }
-
-    if (phase instanceof FML2ClientConnectionPhase specialPhase) {
-      specialPhase.awaitJoinGame().thenAcceptAsync((ignored) -> {
-        player.setConnectedServer(null);
-        continuation.resume();
-      },player.getConnection().eventLoop());
-    }
-  }
 }

src/main/java/org/adde0109/ambassador/velocity/VelocityForgeClientConnectionPhase.java

@@ -1,6 +1,5 @@
 package org.adde0109.ambassador.velocity;
 
-import com.velocitypowered.api.event.Continuation;
 import com.velocitypowered.api.proxy.ServerConnection;
 import com.velocitypowered.api.proxy.server.RegisteredServer;
 import com.velocitypowered.proxy.VelocityServer;
@@ -11,6 +10,7 @@ import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
 import com.velocitypowered.proxy.protocol.packet.LoginPluginMessage;
 import com.velocitypowered.proxy.protocol.packet.LoginPluginResponse;
 
+import java.lang.reflect.InvocationTargetException;
 import java.util.concurrent.CompletableFuture;
 
 public abstract class VelocityForgeClientConnectionPhase implements ClientConnectionPhase {
@@ -30,45 +30,31 @@ public abstract class VelocityForgeClientConnectionPhase implements ClientConnec
   protected VelocityForgeClientConnectionPhase() {
   }
 
-  public void handleLogin(ConnectedPlayer player, VelocityServer server, Continuation continuation) {
+  public RegisteredServer chooseServer(ConnectedPlayer player) {
+    return null;
   }
 
   public CompletableFuture<Boolean> reset(RegisteredServer server, ConnectedPlayer player) {
     return CompletableFuture.completedFuture(false);
   }
 
-  public void complete(VelocityServer server, ConnectedPlayer player, MinecraftConnection connection) {
 
-  }
 
-  final void fireLoginEvent(ConnectedPlayer player, VelocityServer server, Continuation continuation) {
-    payloadManager = new VelocityLoginPayloadManager(player.getConnection());
-    handleLogin(player,server,continuation);
-
-    VelocityForgeHandshakeSessionHandler sessionHandler = new VelocityForgeHandshakeSessionHandler(player.getConnection().getSessionHandler(), this);
-    player.getConnection().setSessionHandler(sessionHandler);
+  final void onFirstLogin(ConnectedPlayer player, VelocityServer server) throws InterruptedException, InvocationTargetException, IllegalAccessException {
   }
 
   public void handleForward(VelocityServerConnection serverConnection, LoginPluginMessage payload) {
   }
 
-  final public void forwardPayload(VelocityServerConnection serverConnection, LoginPluginMessage payload) {
-    handleForward(serverConnection,payload);
-    if (payloadManager == null) {
-      payload.release();
-      return;
-    }
-    payloadManager.sendPayload("fml:loginwrapper",payload.content()).thenAccept((responseData) -> {
-      //Move this to the backend. Backend should have its own forwarder.
-      serverConnection.getConnection().write(new LoginPluginResponse(payload.getId(),responseData.isReadable(),responseData.retain()));
-    });
-    clientPhase = ClientPhase.MODLIST;
-  }
-
   public final VelocityLoginPayloadManager getPayloadManager() {
     return payloadManager;
   }
 
+  public boolean handle(ConnectedPlayer player, LoginPluginResponse response, VelocityServerConnection server) {
+    server.getConnection().write(response.retain());
+    return true;
+  }
+
   public enum ClientPhase {
     VANILLA,
     HANDSHAKE,

src/main/java/org/adde0109/ambassador/velocity/VelocityForgeHandshakeSessionHandler.java

@@ -1,26 +1,29 @@
 package org.adde0109.ambassador.velocity;
 
+import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
+import com.velocitypowered.proxy.connection.backend.VelocityServerConnection;
 import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
 import com.velocitypowered.proxy.protocol.packet.LoginPluginResponse;
 import io.netty.buffer.ByteBuf;
 
 public class VelocityForgeHandshakeSessionHandler implements MinecraftSessionHandler {
   private final MinecraftSessionHandler original;
-  private final VelocityForgeClientConnectionPhase phase;
+  private final ConnectedPlayer player;
 
-  public VelocityForgeHandshakeSessionHandler(MinecraftSessionHandler original, VelocityForgeClientConnectionPhase phase) {
+  public VelocityForgeHandshakeSessionHandler(MinecraftSessionHandler original, ConnectedPlayer player) {
     this.original = original;
-    this.phase = phase;
+    this.player = player;
   }
 
   @Override
   public boolean handle(LoginPluginResponse packet) {
-    if (phase.getPayloadManager().handlePayload(packet)) {
-      return true;
-    } else {
-      return original.handle(packet);
+    if (player.getPhase() instanceof VelocityForgeClientConnectionPhase phase) {
+      if (phase.handle(player,packet,player.getConnectionInFlight())) {
+        return true;
+      }
     }
+    return original.handle(packet);
   }
   @Override
   public void handleUnknown(ByteBuf buf) {

src/main/java/org/adde0109/ambassador/velocity/VelocityHandshakeSessionHandler.java

@@ -4,11 +4,13 @@ import com.velocitypowered.proxy.connection.ConnectionTypes;
 import com.velocitypowered.proxy.connection.MinecraftConnection;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import com.velocitypowered.proxy.connection.client.HandshakeSessionHandler;
+import com.velocitypowered.proxy.network.Connections;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.StateRegistry;
 import com.velocitypowered.proxy.protocol.packet.Handshake;
 import io.netty.buffer.ByteBuf;
 import org.adde0109.ambassador.forge.ForgeConstants;
+import org.adde0109.ambassador.velocity.client.OutboundSuccessHolder;
 
 public class VelocityHandshakeSessionHandler implements MinecraftSessionHandler {
   private final HandshakeSessionHandler original;
@@ -26,8 +28,14 @@ public class VelocityHandshakeSessionHandler implements MinecraftSessionHandler
       final String[] markerSplit = handshake.getServerAddress().split("\0");
       if (connection.getState() == StateRegistry.LOGIN && markerSplit.length > 1) {
         switch (markerSplit[1]) {
-          case "FML2" -> connection.setType(ForgeConstants.ForgeFML2);
-          case "FML3" -> connection.setType(ForgeConstants.ForgeFML3);
+          case "FML2":
+            connection.setType(ForgeConstants.ForgeFML2);
+            connection.getChannel().pipeline().addAfter(Connections.MINECRAFT_ENCODER,ForgeConstants.SERVER_SUCCESS_LISTENER, new OutboundSuccessHolder());
+            break;
+          case "FML3":
+            connection.setType(ForgeConstants.ForgeFML3);
+            connection.getChannel().pipeline().addAfter(Connections.MINECRAFT_ENCODER,ForgeConstants.SERVER_SUCCESS_LISTENER, new OutboundSuccessHolder());
+            break;
         }
       }
     }

src/main/java/org/adde0109/ambassador/velocity/backend/ForgeHandshakeSessionHandler.java

@@ -2,6 +2,7 @@ package org.adde0109.ambassador.velocity.backend;
 
 import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
+import com.velocitypowered.proxy.connection.backend.BackendConnectionPhases;
 import com.velocitypowered.proxy.connection.backend.LoginSessionHandler;
 import com.velocitypowered.proxy.connection.backend.VelocityServerConnection;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
@@ -31,16 +32,11 @@ public class ForgeHandshakeSessionHandler implements MinecraftSessionHandler {
   @Override
   public boolean handle(LoginPluginMessage packet) {
     if (packet.getChannel().equals("fml:loginwrapper")) {
-      if (!(serverConnection.getConnection().getType() instanceof ForgeFMLConnectionType)) {
-        if (!(serverConnection.getPlayer().getConnection().getType() instanceof ForgeFMLConnectionType clientType)) {
-          final String reason = "This server has mods that require Forge to be installed on the client. Contact your server admin for more details.";
-          original.handle(Disconnect.create(Component.text(reason, NamedTextColor.RED),serverConnection.getPlayer().getProtocolVersion()));
-          return true;
-        }
-        serverConnection.getConnection().setType(clientType);
-        serverConnection.setConnectionPhase(clientType.getInitialBackendPhase());
+      if (serverConnection.getPhase() == BackendConnectionPhases.UNKNOWN) {
+        VelocityForgeBackendConnectionPhase.NOT_STARTED.handle(serverConnection,serverConnection.getPlayer(),packet);
+      } else if (serverConnection.getPhase() instanceof VelocityForgeBackendConnectionPhase phase1) {
+        phase1.handle(serverConnection,serverConnection.getPlayer(),packet);
       }
-      ((VelocityForgeBackendConnectionPhase) serverConnection.getPhase()).handle(serverConnection,serverConnection.getPlayer(),packet);
       return true;
     }
     return original.handle(packet);
@@ -48,8 +44,8 @@ public class ForgeHandshakeSessionHandler implements MinecraftSessionHandler {
 
   @Override
   public boolean handle(ServerLoginSuccess packet) {
-    if ((serverConnection.getPlayer().getPhase() instanceof VelocityForgeClientConnectionPhase phase)) {
-      phase.complete(server,serverConnection.getPlayer(),serverConnection.getPlayer().getConnection());
+    if ((serverConnection.getPhase() instanceof VelocityForgeBackendConnectionPhase phase)) {
+      phase.onLoginSuccess(serverConnection,serverConnection.getPlayer());
     }
     return original.handle(packet);
   }

src/main/java/org/adde0109/ambassador/velocity/backend/VelocityForgeBackendConnectionPhase.java

@@ -1,26 +1,51 @@
 package org.adde0109.ambassador.velocity.backend;
 
-import com.velocitypowered.proxy.VelocityServer;
+import com.velocitypowered.proxy.connection.MinecraftConnection;
 import com.velocitypowered.proxy.connection.backend.BackendConnectionPhase;
 import com.velocitypowered.proxy.connection.backend.VelocityServerConnection;
 import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
+import com.velocitypowered.proxy.protocol.StateRegistry;
 import com.velocitypowered.proxy.protocol.packet.LoginPluginMessage;
-import io.netty.buffer.ByteBuf;
-import io.netty.util.ReferenceCountUtil;
+import org.adde0109.ambassador.forge.ForgeConstants;
 import org.adde0109.ambassador.velocity.VelocityForgeClientConnectionPhase;
 
-import java.util.ArrayList;
-import java.util.List;
+public enum VelocityForgeBackendConnectionPhase implements BackendConnectionPhase {
+  NOT_STARTED() {
+    @Override
+    VelocityForgeBackendConnectionPhase nextPhase() {
+      return WAITING_FOR_ACK;
+    }
+  },
+  WAITING_FOR_ACK() {
+    @Override
+    public void onLoginSuccess(VelocityServerConnection serverCon, ConnectedPlayer player) {
+      serverCon.setConnectionPhase(VelocityForgeBackendConnectionPhase.COMPLETE);
 
-public class VelocityForgeBackendConnectionPhase implements BackendConnectionPhase {
+      MinecraftConnection connection = player.getConnection();
+      connection.getChannel().pipeline().remove(ForgeConstants.SERVER_SUCCESS_LISTENER);
+      connection.setState(StateRegistry.PLAY);
+    }
+  },
 
+  COMPLETE() {
+    @Override
+    public boolean consideredComplete() {
+      return true;
+    }
+  };
 
-  public VelocityForgeBackendConnectionPhase() {
+  VelocityForgeBackendConnectionPhase() {
   }
 
   public void handle(VelocityServerConnection server, ConnectedPlayer player, LoginPluginMessage message) {
+
+
+    VelocityForgeBackendConnectionPhase newPhase = nextPhase();
+
+    server.setConnectionPhase(newPhase);
+
     VelocityForgeClientConnectionPhase clientPhase = ((VelocityForgeClientConnectionPhase) player.getPhase());
-    if (clientPhase.clientPhase == VelocityForgeClientConnectionPhase.ClientPhase.VANILLA) {
+    if (player.getConnection().getState() != StateRegistry.LOGIN) {
       final LoginPluginMessage msg = message;
 
       msg.content().retain().discardSomeReadBytes();
@@ -28,14 +53,25 @@ public class VelocityForgeBackendConnectionPhase implements BackendConnectionPha
       server.getConnection().getChannel().config().setAutoRead(false);
       clientPhase.reset(server.getServer(),player).thenAccept((success) -> {
         if (success) {
-          clientPhase.forwardPayload(server,msg);
+          player.getConnection().write(msg);
           server.getConnection().getChannel().config().setAutoRead(true);
         } else {
           msg.release();
         }
       });
     } else {
-      clientPhase.forwardPayload(server, (LoginPluginMessage) message.retain());
+      player.getConnection().write(message.retain());
     }
   }
+
+  public void onLoginSuccess(VelocityServerConnection serverCon, ConnectedPlayer player) {
+
+  }
+  VelocityForgeBackendConnectionPhase nextPhase() {
+    return this;
+  }
+  public boolean consideredComplete() {
+    return false;
+  }
+
 }

src/main/java/org/adde0109/ambassador/velocity/client/OutboundSuccessHolder.java

@@ -0,0 +1,28 @@
+package org.adde0109.ambassador.velocity.client;
+
+import com.velocitypowered.proxy.protocol.packet.ServerLoginSuccess;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelOutboundHandlerAdapter;
+import io.netty.channel.ChannelPromise;
+
+public class OutboundSuccessHolder extends ChannelOutboundHandlerAdapter {
+
+  private ServerLoginSuccess packet;
+
+  @Override
+  public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
+    if ((msg instanceof ServerLoginSuccess packet)) {
+      this.packet = packet;
+    } else {
+      ctx.write(msg, promise);
+    }
+  }
+
+  @Override
+  public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
+    if (ctx.channel().isActive()) {
+      ctx.write(packet, ctx.voidPromise());
+      ctx.flush();
+    }
+  }
+}