--- a/net/minecraft/network/Connection.java
+++ b/net/minecraft/network/Connection.java
@@ -73,20 +_,25 @@
     public static final Marker PACKET_RECEIVED_MARKER = Util.make(MarkerFactory.getMarker("PACKET_RECEIVED"), marker -> marker.add(PACKET_MARKER));
     public static final Marker PACKET_SENT_MARKER = Util.make(MarkerFactory.getMarker("PACKET_SENT"), marker -> marker.add(PACKET_MARKER));
     public static final Supplier<NioEventLoopGroup> NETWORK_WORKER_GROUP = Suppliers.memoize(
-        () -> new NioEventLoopGroup(0, new ThreadFactoryBuilder().setNameFormat("Netty Client IO #%d").setDaemon(true).build())
+        () -> new NioEventLoopGroup(0, new ThreadFactoryBuilder().setNameFormat("Netty Client IO #%d").setDaemon(true).setUncaughtExceptionHandler(new net.minecraft.DefaultUncaughtExceptionHandlerWithName(LOGGER)).build()) // Paper
     );
     public static final Supplier<EpollEventLoopGroup> NETWORK_EPOLL_WORKER_GROUP = Suppliers.memoize(
-        () -> new EpollEventLoopGroup(0, new ThreadFactoryBuilder().setNameFormat("Netty Epoll Client IO #%d").setDaemon(true).build())
+        () -> new EpollEventLoopGroup(0, new ThreadFactoryBuilder().setNameFormat("Netty Epoll Client IO #%d").setDaemon(true).setUncaughtExceptionHandler(new net.minecraft.DefaultUncaughtExceptionHandlerWithName(LOGGER)).build()) // Paper
     );
     public static final Supplier<DefaultEventLoopGroup> LOCAL_WORKER_GROUP = Suppliers.memoize(
-        () -> new DefaultEventLoopGroup(0, new ThreadFactoryBuilder().setNameFormat("Netty Local Client IO #%d").setDaemon(true).build())
+        () -> new DefaultEventLoopGroup(0, new ThreadFactoryBuilder().setNameFormat("Netty Local Client IO #%d").setDaemon(true).setUncaughtExceptionHandler(new net.minecraft.DefaultUncaughtExceptionHandlerWithName(LOGGER)).build()) // Paper
     );
     private static final ProtocolInfo<ServerHandshakePacketListener> INITIAL_PROTOCOL = HandshakeProtocols.SERVERBOUND;
     private final PacketFlow receiving;
     private volatile boolean sendLoginDisconnect = true;
-    private final Queue<Consumer<Connection>> pendingActions = Queues.newConcurrentLinkedQueue();
-    private Channel channel;
-    private SocketAddress address;
+    private final Queue<WrappedConsumer> pendingActions = Queues.newConcurrentLinkedQueue(); // Paper - Optimize network
+    public Channel channel;
+    public SocketAddress address;
+    // Spigot start
+    public java.util.UUID spoofedUUID;
+    public com.mojang.authlib.properties.Property[] spoofedProfile;
+    public boolean preparing = true;
+    // Spigot end
     @Nullable
     private volatile PacketListener disconnectListener;
     @Nullable
@@ -105,6 +_,47 @@
     private volatile DisconnectionDetails delayedDisconnect;
     @Nullable
     BandwidthDebugMonitor bandwidthDebugMonitor;
+    public String hostname = ""; // CraftBukkit - add field
+    // Paper start - NetworkClient implementation
+    public int protocolVersion;
+    public java.net.InetSocketAddress virtualHost;
+    private static boolean enableExplicitFlush = Boolean.getBoolean("paper.explicit-flush"); // Paper - Disable explicit network manager flushing
+    // Paper end
+    // Paper start - add utility methods
+    public final net.minecraft.server.level.ServerPlayer getPlayer() {
+        if (this.packetListener instanceof net.minecraft.server.network.ServerGamePacketListenerImpl impl) {
+            return impl.player;
+        } else if (this.packetListener instanceof net.minecraft.server.network.ServerCommonPacketListenerImpl impl) {
+            return null;
+        }
+        return null;
+    }
+    // Paper end - add utility methods
+    // Paper start - packet limiter
+    protected final Object PACKET_LIMIT_LOCK = new Object();
+    protected final @Nullable io.papermc.paper.util.IntervalledCounter allPacketCounts = io.papermc.paper.configuration.GlobalConfiguration.get().packetLimiter.allPackets.isEnabled() ? new io.papermc.paper.util.IntervalledCounter(
+        (long)(io.papermc.paper.configuration.GlobalConfiguration.get().packetLimiter.allPackets.interval() * 1.0e9)
+    ) : null;
+    protected final java.util.Map<Class<? extends net.minecraft.network.protocol.Packet<?>>, io.papermc.paper.util.IntervalledCounter> packetSpecificLimits = new java.util.HashMap<>();
+
+    private boolean stopReadingPackets;
+    private void killForPacketSpam() {
+        this.sendPacket(new ClientboundDisconnectPacket(io.papermc.paper.adventure.PaperAdventure.asVanilla(io.papermc.paper.configuration.GlobalConfiguration.get().packetLimiter.kickMessage)), PacketSendListener.thenRun(() -> {
+            this.disconnect(io.papermc.paper.adventure.PaperAdventure.asVanilla(io.papermc.paper.configuration.GlobalConfiguration.get().packetLimiter.kickMessage));
+        }), true);
+        this.setReadOnly();
+        this.stopReadingPackets = true;
+    }
+    // Paper end - packet limiter
+    @Nullable public SocketAddress haProxyAddress; // Paper - Add API to get player's proxy address
+    public @Nullable java.util.Optional<net.minecraft.network.chat.Component> legacySavedLoginEventResultOverride; // Paper - playerloginevent
+    public boolean handledLegacyLoginEvent; // Paper - playerloginevent
+    public @Nullable net.minecraft.server.level.ServerPlayer savedPlayerForLegacyEvents; // Paper - playerloginevent & PlayerSpawnLocationEvent
+    public @Nullable org.bukkit.event.player.PlayerResourcePackStatusEvent.Status resourcePackStatus; // Paper
+    // Paper start - Optimize network
+    public boolean isPending = true;
+    public boolean queueImmunity;
+    // Paper end - Optimize network
 
     public Connection(PacketFlow receiving) {
         this.receiving = receiving;
@@ -115,6 +_,7 @@
         super.channelActive(context);
         this.channel = context.channel();
         this.address = this.channel.remoteAddress();
+        this.preparing = false; // Spigot
         if (this.delayedDisconnect != null) {
             this.disconnect(this.delayedDisconnect);
         }
@@ -127,14 +_,31 @@
 
     @Override
     public void exceptionCaught(ChannelHandlerContext context, Throwable exception) {
+        // Paper start - Handle large packets disconnecting client
+        if (exception instanceof io.netty.handler.codec.EncoderException && exception.getCause() instanceof PacketEncoder.PacketTooLargeException packetTooLargeException) {
+            final Packet<?> packet = packetTooLargeException.getPacket();
+            if (packet.packetTooLarge(this)) {
+                ProtocolSwapHandler.handleOutboundTerminalPacket(context, packet);
+                return;
+            } else if (packet.isSkippable()) {
+                Connection.LOGGER.debug("Skipping packet due to errors", exception.getCause());
+                ProtocolSwapHandler.handleOutboundTerminalPacket(context, packet);
+                return;
+            } else {
+                exception = exception.getCause();
+            }
+        }
+        // Paper end - Handle large packets disconnecting client
         if (exception instanceof SkipPacketException) {
             LOGGER.debug("Skipping packet due to errors", exception.getCause());
         } else {
             boolean flag = !this.handlingFault;
             this.handlingFault = true;
             if (this.channel.isOpen()) {
+                net.minecraft.server.level.ServerPlayer player = this.getPlayer(); // Paper - Add API for quit reason
                 if (exception instanceof TimeoutException) {
                     LOGGER.debug("Timeout", exception);
+                    if (player != null) player.quitReason = org.bukkit.event.player.PlayerQuitEvent.QuitReason.TIMED_OUT; // Paper - Add API for quit reason
                     this.disconnect(Component.translatable("disconnect.timeout"));
                 } else {
                     Component component = Component.translatable("disconnect.genericReason", "Internal Exception: " + exception);
@@ -146,9 +_,11 @@
                         disconnectionDetails = new DisconnectionDetails(component);
                     }
 
+                    if (player != null) player.quitReason = org.bukkit.event.player.PlayerQuitEvent.QuitReason.ERRONEOUS_STATE; // Paper - Add API for quit reason
                     if (flag) {
                         LOGGER.debug("Failed to sent packet", exception);
-                        if (this.getSending() == PacketFlow.CLIENTBOUND) {
+                        boolean doesDisconnectExist = this.packetListener.protocol() != ConnectionProtocol.STATUS && this.packetListener.protocol() != ConnectionProtocol.HANDSHAKING; // Paper
+                        if (this.getSending() == PacketFlow.CLIENTBOUND && doesDisconnectExist) { // Paper
                             Packet<?> packet = (Packet<?>)(this.sendLoginDisconnect
                                 ? new ClientboundLoginDisconnectPacket(component)
                                 : new ClientboundDisconnectPacket(component));
@@ -165,6 +_,7 @@
                 }
             }
         }
+        if (net.minecraft.server.MinecraftServer.getServer().isDebugging()) io.papermc.paper.util.TraceUtil.printStackTrace(exception); // Spigot // Paper
     }
 
     @Override
@@ -174,10 +_,60 @@
             if (packetListener == null) {
                 throw new IllegalStateException("Received a packet before the packet listener was initialized");
             } else {
+                // Paper start - packet limiter
+                if (this.stopReadingPackets) {
+                    return;
+                }
+                if (this.allPacketCounts != null ||
+                    io.papermc.paper.configuration.GlobalConfiguration.get().packetLimiter.overrides.containsKey(packet.getClass())) {
+                    long time = System.nanoTime();
+                    synchronized (PACKET_LIMIT_LOCK) {
+                        if (this.allPacketCounts != null) {
+                            this.allPacketCounts.updateAndAdd(1, time);
+                            if (this.allPacketCounts.getRate() >= io.papermc.paper.configuration.GlobalConfiguration.get().packetLimiter.allPackets.maxPacketRate()) {
+                                this.killForPacketSpam();
+                                return;
+                            }
+                        }
+
+                        for (Class<?> check = packet.getClass(); check != Object.class; check = check.getSuperclass()) {
+                            io.papermc.paper.configuration.GlobalConfiguration.PacketLimiter.PacketLimit packetSpecificLimit =
+                                io.papermc.paper.configuration.GlobalConfiguration.get().packetLimiter.overrides.get(check);
+                            if (packetSpecificLimit == null || !packetSpecificLimit.isEnabled()) {
+                                continue;
+                            }
+                            io.papermc.paper.util.IntervalledCounter counter = this.packetSpecificLimits.computeIfAbsent((Class)check, (clazz) -> {
+                                return new io.papermc.paper.util.IntervalledCounter((long)(packetSpecificLimit.interval() * 1.0e9));
+                            });
+                            counter.updateAndAdd(1, time);
+                            if (counter.getRate() >= packetSpecificLimit.maxPacketRate()) {
+                                switch (packetSpecificLimit.action()) {
+                                    case DROP:
+                                        return;
+                                    case KICK:
+                                        String deobfedPacketName = io.papermc.paper.util.ObfHelper.INSTANCE.deobfClassName(check.getName());
+
+                                        String playerName;
+                                        if (this.packetListener instanceof net.minecraft.server.network.ServerCommonPacketListenerImpl impl) {
+                                            playerName = impl.getOwner().name();
+                                        } else {
+                                            playerName = this.getLoggableAddress(net.minecraft.server.MinecraftServer.getServer().logIPs());
+                                        }
+
+                                        Connection.LOGGER.warn("{} kicked for packet spamming: {}", playerName, deobfedPacketName.substring(deobfedPacketName.lastIndexOf(".") + 1));
+                                        this.killForPacketSpam();
+                                        return;
+                                }
+                            }
+                        }
+                    }
+                }
+                // Paper end - packet limiter
                 if (packetListener.shouldHandleMessage(packet)) {
                     try {
                         genericsFtw(packet, packetListener);
                     } catch (RunningOnDifferentThreadException var5) {
+                    } catch (io.papermc.paper.util.ServerStopRejectedExecutionException ignored) { // Paper - do not prematurely disconnect players on stop
                     } catch (RejectedExecutionException var6) {
                         this.disconnect(Component.translatable("multiplayer.disconnect.server_shutdown"));
                     } catch (ClassCastException var7) {
@@ -308,11 +_,38 @@
     }
 
     public void send(Packet<?> packet, @Nullable ChannelFutureListener sendListener, boolean flush) {
-        if (this.isConnected()) {
-            this.flushQueue();
+        // Paper start - Optimize network: Handle oversized packets better
+        final boolean connected = this.isConnected();
+        if (!connected && !this.preparing) {
+            return;
+        }
+
+        packet.onPacketDispatch(this.getPlayer());
+        if (connected && (InnerUtil.canSendImmediate(this, packet)
+            || (io.papermc.paper.util.MCUtil.isMainThread() && packet.isReady() && this.pendingActions.isEmpty()
+            && (packet.getExtraPackets() == null || packet.getExtraPackets().isEmpty())))) {
             this.sendPacket(packet, sendListener, flush);
         } else {
-            this.pendingActions.add(connection -> connection.sendPacket(packet, sendListener, flush));
+            // Write the packets to the queue, then flush - antixray hooks there already
+            final java.util.List<Packet<?>> extraPackets = InnerUtil.buildExtraPackets(packet);
+            final boolean hasExtraPackets = extraPackets != null && !extraPackets.isEmpty();
+            if (!hasExtraPackets) {
+                this.pendingActions.add(new PacketSendAction(packet, sendListener, flush));
+            } else {
+                final java.util.List<PacketSendAction> actions = new java.util.ArrayList<>(1 + extraPackets.size());
+                actions.add(new PacketSendAction(packet, null, false)); // Delay the future listener until the end of the extra packets
+
+                for (int i = 0, len = extraPackets.size(); i < len;) {
+                    final Packet<?> extraPacket = extraPackets.get(i);
+                    final boolean end = ++i == len;
+                    actions.add(new PacketSendAction(extraPacket, end ? sendListener : null, end)); // Append listener to the end
+                }
+
+                this.pendingActions.addAll(actions);
+            }
+
+            this.flushQueue();
+            // Paper end - Optimize network
         }
     }
 
@@ -321,7 +_,7 @@
             this.flushQueue();
             action.accept(this);
         } else {
-            this.pendingActions.add(action);
+            this.pendingActions.add(new WrappedConsumer(action)); // Paper - Optimize network
         }
     }
 
@@ -335,21 +_,41 @@
     }
 
     private void doSendPacket(Packet<?> packet, @Nullable ChannelFutureListener sendListener, boolean flush) {
+        // Paper start - Optimize network
+        final net.minecraft.server.level.ServerPlayer player = this.getPlayer();
+        if (!this.isConnected()) {
+            packet.onPacketDispatchFinish(player, null);
+            return;
+        }
+        try {
+        final ChannelFuture channelFuture;
+        // Paper end - Optimize network
         if (sendListener != null) {
-            ChannelFuture channelFuture = flush ? this.channel.writeAndFlush(packet) : this.channel.write(packet);
+            channelFuture = flush ? this.channel.writeAndFlush(packet) : this.channel.write(packet); // Paper - Optimize network
             channelFuture.addListener(sendListener);
         } else if (flush) {
-            this.channel.writeAndFlush(packet, this.channel.voidPromise());
+            channelFuture = this.channel.writeAndFlush(packet, this.channel.voidPromise()); // Paper - Optimize network
         } else {
-            this.channel.write(packet, this.channel.voidPromise());
-        }
+            channelFuture = this.channel.write(packet, this.channel.voidPromise()); // Paper - Optimize network
+        }
+
+        // Paper start - Optimize network
+        if (packet.hasFinishListener()) {
+            channelFuture.addListener((ChannelFutureListener) future -> packet.onPacketDispatchFinish(player, future));
+        }
+        } catch (final Exception e) {
+            LOGGER.error("NetworkException: {}", player, e);
+            this.disconnect(Component.translatable("disconnect.genericReason", "Internal Exception: " + e.getMessage()));
+            packet.onPacketDispatchFinish(player, null);
+        }
+        // Paper end - Optimize network
     }
 
     public void flushChannel() {
         if (this.isConnected()) {
             this.flush();
         } else {
-            this.pendingActions.add(Connection::flush);
+            this.pendingActions.add(new WrappedConsumer(Connection::flush)); // Paper - Optimize network
         }
     }
 
@@ -361,21 +_,82 @@
         }
     }
 
-    private void flushQueue() {
-        if (this.channel != null && this.channel.isOpen()) {
+    // Paper start - Optimize network: Rewrite this to be safer if ran off main thread
+    private boolean flushQueue() {
+        if (!this.isConnected()) {
+            return true;
+        }
+        if (io.papermc.paper.util.MCUtil.isMainThread()) {
+            return this.processQueue();
+        } else if (this.isPending) {
+            // Should only happen during login/status stages
             synchronized (this.pendingActions) {
-                Consumer<Connection> consumer;
-                while ((consumer = this.pendingActions.poll()) != null) {
-                    consumer.accept(this);
+                return this.processQueue();
+            }
+        }
+        return false;
+    }
+
+    private boolean processQueue() {
+        if (this.pendingActions.isEmpty()) {
+            return true;
+        }
+
+        // If we are on main, we are safe here in that nothing else should be processing queue off main anymore
+        // But if we are not on main due to login/status, the parent is synchronized on packetQueue
+        final java.util.Iterator<WrappedConsumer> iterator = this.pendingActions.iterator();
+        while (iterator.hasNext()) {
+            final WrappedConsumer queued = iterator.next(); // poll -> peek
+
+            // Fix NPE (Spigot bug caused by handleDisconnection())
+            if (queued == null) {
+                return true;
+            }
+
+            if (queued.isConsumed()) {
+                continue;
+            }
+
+            if (queued instanceof PacketSendAction packetSendAction) {
+                final Packet<?> packet = packetSendAction.packet;
+                if (!packet.isReady()) {
+                    return false;
                 }
             }
+
+            iterator.remove();
+            if (queued.tryMarkConsumed()) {
+                queued.accept(this);
+            }
         }
+        return true;
     }
+    // Paper end - Optimize network
 
+    private static final int MAX_PER_TICK = io.papermc.paper.configuration.GlobalConfiguration.get().misc.maxJoinsPerTick; // Paper - Buffer joins to world
+    private static int joinAttemptsThisTick; // Paper - Buffer joins to world
+    private static int currTick; // Paper - Buffer joins to world
     public void tick() {
         this.flushQueue();
+        // Paper start - Buffer joins to world
+        if (Connection.currTick != net.minecraft.server.MinecraftServer.currentTick) {
+            Connection.currTick = net.minecraft.server.MinecraftServer.currentTick;
+            Connection.joinAttemptsThisTick = 0;
+        }
+        // Paper end - Buffer joins to world
         if (this.packetListener instanceof TickablePacketListener tickablePacketListener) {
+            // Paper start - Buffer joins to world
+            if (!(this.packetListener instanceof net.minecraft.server.network.ServerLoginPacketListenerImpl loginPacketListener)
+                || loginPacketListener.state != net.minecraft.server.network.ServerLoginPacketListenerImpl.State.VERIFYING
+                || Connection.joinAttemptsThisTick++ < MAX_PER_TICK) {
+            // Paper start - detailed watchdog information
+            net.minecraft.network.PacketProcessor.packetProcessing.push(this.packetListener);
+            try {
             tickablePacketListener.tick();
+            } finally {
+                net.minecraft.network.PacketProcessor.packetProcessing.pop();
+            } // Paper end - detailed watchdog information
+            } // Paper end - Buffer joins to world
         }
 
         if (!this.isConnected() && !this.disconnectionHandled) {
@@ -383,7 +_,7 @@
         }
 
         if (this.channel != null) {
-            this.channel.flush();
+            if (enableExplicitFlush) this.channel.eventLoop().execute(() -> this.channel.flush()); // Paper - Disable explicit network manager flushing; we don't need to explicit flush here, but allow opt in incase issues are found to a better version
         }
 
         if (this.tickCount++ % 20 == 0) {
@@ -419,12 +_,14 @@
     }
 
     public void disconnect(DisconnectionDetails disconnectionDetails) {
+        this.preparing = false; // Spigot
+        this.clearPacketQueue(); // Paper - Optimize network
         if (this.channel == null) {
             this.delayedDisconnect = disconnectionDetails;
         }
 
         if (this.isConnected()) {
-            this.channel.close().awaitUninterruptibly();
+            this.channel.close(); // We can't wait as this may be called from an event loop.
             this.disconnectionDetails = disconnectionDetails;
         }
     }
@@ -537,11 +_,22 @@
         return connection;
     }
 
-    public void setEncryptionKey(Cipher decryptingCipher, Cipher encryptingCipher) {
-        this.encrypted = true;
-        this.channel.pipeline().addBefore("splitter", "decrypt", new CipherDecoder(decryptingCipher));
-        this.channel.pipeline().addBefore("prepender", "encrypt", new CipherEncoder(encryptingCipher));
+    // Paper start - Use Velocity cipher
+    public void setEncryptionKey(javax.crypto.SecretKey key) throws net.minecraft.util.CryptException {
+        if (!this.encrypted) {
+            try {
+                com.velocitypowered.natives.encryption.VelocityCipher decryptionCipher = com.velocitypowered.natives.util.Natives.cipher.get().forDecryption(key);
+                com.velocitypowered.natives.encryption.VelocityCipher encryptionCipher = com.velocitypowered.natives.util.Natives.cipher.get().forEncryption(key);
+
+                this.encrypted = true;
+                this.channel.pipeline().addBefore("splitter", "decrypt", new CipherDecoder(decryptionCipher));
+                this.channel.pipeline().addBefore("prepender", "encrypt", new CipherEncoder(encryptionCipher));
+            } catch (java.security.GeneralSecurityException e) {
+                throw new net.minecraft.util.CryptException(e);
+            }
+        }
     }
+    // Paper end - Use Velocity cipher
 
     public boolean isEncrypted() {
         return this.encrypted;
@@ -571,19 +_,28 @@
         }
     }
 
+    // Paper start - add proper async disconnect
+    public void enableAutoRead() {
+        if (this.channel != null) {
+            this.channel.config().setAutoRead(true);
+        }
+    }
+    // Paper end - add proper async disconnect
     public void setupCompression(int threshold, boolean validateDecompressed) {
         if (threshold >= 0) {
+            com.velocitypowered.natives.compression.VelocityCompressor compressor = com.velocitypowered.natives.util.Natives.compress.get().create(io.papermc.paper.configuration.GlobalConfiguration.get().misc.compressionLevel.or(-1)); // Paper - Use Velocity cipher
             if (this.channel.pipeline().get("decompress") instanceof CompressionDecoder compressionDecoder) {
-                compressionDecoder.setThreshold(threshold, validateDecompressed);
+                compressionDecoder.setThreshold(compressor, threshold, validateDecompressed); // Paper - Use Velocity cipher
             } else {
-                this.channel.pipeline().addAfter("splitter", "decompress", new CompressionDecoder(threshold, validateDecompressed));
+                this.channel.pipeline().addAfter("splitter", "decompress", new CompressionDecoder(compressor, threshold, validateDecompressed)); // Paper - Use Velocity cipher
             }
 
             if (this.channel.pipeline().get("compress") instanceof CompressionEncoder compressionEncoder) {
                 compressionEncoder.setThreshold(threshold);
             } else {
-                this.channel.pipeline().addAfter("prepender", "compress", new CompressionEncoder(threshold));
+                this.channel.pipeline().addAfter("prepender", "compress", new CompressionEncoder(compressor, threshold)); // Paper - Use Velocity cipher
             }
+            this.channel.pipeline().fireUserEventTriggered(io.papermc.paper.network.ConnectionEvent.COMPRESSION_THRESHOLD_SET); // Paper - Add Channel initialization listeners
         } else {
             if (this.channel.pipeline().get("decompress") instanceof CompressionDecoder) {
                 this.channel.pipeline().remove("decompress");
@@ -592,13 +_,14 @@
             if (this.channel.pipeline().get("compress") instanceof CompressionEncoder) {
                 this.channel.pipeline().remove("compress");
             }
+            this.channel.pipeline().fireUserEventTriggered(io.papermc.paper.network.ConnectionEvent.COMPRESSION_DISABLED); // Paper - Add Channel initialization listeners
         }
     }
 
     public void handleDisconnection() {
         if (this.channel != null && !this.channel.isOpen()) {
             if (this.disconnectionHandled) {
-                LOGGER.warn("handleDisconnection() called twice");
+                // LOGGER.warn("handleDisconnection() called twice"); // Paper - Don't log useless message
             } else {
                 this.disconnectionHandled = true;
                 PacketListener packetListener = this.getPacketListener();
@@ -609,6 +_,26 @@
                     );
                     packetListener1.onDisconnect(disconnectionDetails);
                 }
+                this.clearPacketQueue(); // Paper - Optimize network
+                // Paper start - Add PlayerConnectionCloseEvent
+                if (packetListener instanceof net.minecraft.server.network.ServerCommonPacketListenerImpl commonPacketListener) {
+                    /* Player was logged in, either game listener or configuration listener */
+                    final com.mojang.authlib.GameProfile profile = commonPacketListener.getOwner();
+                    new com.destroystokyo.paper.event.player.PlayerConnectionCloseEvent(profile.id(),
+                        profile.name(), ((InetSocketAddress) this.address).getAddress(), false).callEvent();
+                } else if (packetListener instanceof net.minecraft.server.network.ServerLoginPacketListenerImpl loginListener) {
+                    /* Player is login stage */
+                    switch (loginListener.state) {
+                        case VERIFYING:
+                        case WAITING_FOR_DUPE_DISCONNECT:
+                        case PROTOCOL_SWITCHING:
+                        case ACCEPTED:
+                            final com.mojang.authlib.GameProfile profile = loginListener.authenticatedProfile; /* Should be non-null at this stage */
+                            new com.destroystokyo.paper.event.player.PlayerConnectionCloseEvent(profile.id(), profile.name(),
+                                ((InetSocketAddress) this.address).getAddress(), false).callEvent();
+                    }
+                }
+                // Paper end - Add PlayerConnectionCloseEvent
             }
         }
     }
@@ -624,4 +_,97 @@
     public void setBandwidthLogger(LocalSampleLogger bandwithLogger) {
         this.bandwidthDebugMonitor = new BandwidthDebugMonitor(bandwithLogger);
     }
+
+    // Paper start - Optimize network
+    public void clearPacketQueue() {
+        final net.minecraft.server.level.ServerPlayer player = getPlayer();
+        for (final Consumer<Connection> queuedAction : this.pendingActions) {
+            if (queuedAction instanceof PacketSendAction packetSendAction) {
+                final Packet<?> packet = packetSendAction.packet;
+                if (packet.hasFinishListener()) {
+                    packet.onPacketDispatchFinish(player, null);
+                }
+            }
+        }
+        this.pendingActions.clear();
+    }
+
+    private static class InnerUtil { // Attempt to hide these methods from ProtocolLib, so it doesn't accidently pick them up.
+
+        @Nullable
+        private static java.util.List<Packet<?>> buildExtraPackets(final Packet<?> packet) {
+            final java.util.List<Packet<?>> extra = packet.getExtraPackets();
+            if (extra == null || extra.isEmpty()) {
+                return null;
+            }
+
+            final java.util.List<Packet<?>> ret = new java.util.ArrayList<>(1 + extra.size());
+            buildExtraPackets0(extra, ret);
+            return ret;
+        }
+
+        private static void buildExtraPackets0(final java.util.List<Packet<?>> extraPackets, final java.util.List<Packet<?>> into) {
+            for (final Packet<?> extra : extraPackets) {
+                into.add(extra);
+                final java.util.List<Packet<?>> extraExtra = extra.getExtraPackets();
+                if (extraExtra != null && !extraExtra.isEmpty()) {
+                    buildExtraPackets0(extraExtra, into);
+                }
+            }
+        }
+
+        private static boolean canSendImmediate(final Connection networkManager, final net.minecraft.network.protocol.Packet<?> packet) {
+            return networkManager.isPending || networkManager.packetListener.protocol() != ConnectionProtocol.PLAY ||
+                packet instanceof net.minecraft.network.protocol.common.ClientboundKeepAlivePacket ||
+                packet instanceof net.minecraft.network.protocol.game.ClientboundPlayerChatPacket ||
+                packet instanceof net.minecraft.network.protocol.game.ClientboundSystemChatPacket ||
+                packet instanceof net.minecraft.network.protocol.game.ClientboundDisguisedChatPacket ||
+                packet instanceof net.minecraft.network.protocol.game.ClientboundCommandSuggestionsPacket ||
+                packet instanceof net.minecraft.network.protocol.game.ClientboundSetTitleTextPacket ||
+                packet instanceof net.minecraft.network.protocol.game.ClientboundSetSubtitleTextPacket ||
+                packet instanceof net.minecraft.network.protocol.game.ClientboundSetActionBarTextPacket ||
+                packet instanceof net.minecraft.network.protocol.game.ClientboundSetTitlesAnimationPacket ||
+                packet instanceof net.minecraft.network.protocol.game.ClientboundClearTitlesPacket ||
+                packet instanceof net.minecraft.network.protocol.game.ClientboundSoundPacket ||
+                packet instanceof net.minecraft.network.protocol.game.ClientboundSoundEntityPacket ||
+                packet instanceof net.minecraft.network.protocol.game.ClientboundStopSoundPacket ||
+                packet instanceof net.minecraft.network.protocol.game.ClientboundLevelParticlesPacket ||
+                packet instanceof net.minecraft.network.protocol.game.ClientboundPlayerInfoUpdatePacket ||
+                packet instanceof net.minecraft.network.protocol.game.ClientboundPlayerInfoRemovePacket ||
+                packet instanceof net.minecraft.network.protocol.game.ClientboundBossEventPacket ||
+                packet instanceof net.minecraft.network.protocol.ping.ClientboundPongResponsePacket;
+        }
+    }
+
+    private static class WrappedConsumer implements Consumer<Connection> {
+        private final Consumer<Connection> delegate;
+        private final java.util.concurrent.atomic.AtomicBoolean consumed = new java.util.concurrent.atomic.AtomicBoolean(false);
+
+        private WrappedConsumer(final Consumer<Connection> delegate) {
+            this.delegate = delegate;
+        }
+
+        @Override
+        public void accept(final Connection connection) {
+            this.delegate.accept(connection);
+        }
+
+        public boolean tryMarkConsumed() {
+            return consumed.compareAndSet(false, true);
+        }
+
+        public boolean isConsumed() {
+            return consumed.get();
+        }
+    }
+
+    private static final class PacketSendAction extends WrappedConsumer {
+        private final Packet<?> packet;
+
+        private PacketSendAction(final Packet<?> packet, @Nullable final ChannelFutureListener channelFutureListener, final boolean flush) {
+            super(connection -> connection.sendPacket(packet, channelFutureListener, flush));
+            this.packet = packet;
+        }
+    }
+    // Paper end - Optimize network
 }
