--- a/net/minecraft/network/Connection.java
+++ b/net/minecraft/network/Connection.java
@@ -82,13 +82,13 @@
         marker.add(Connection.PACKET_MARKER);
     });
     public static final Supplier<NioEventLoopGroup> NETWORK_WORKER_GROUP = Suppliers.memoize(() -> {
-        return new NioEventLoopGroup(0, (new ThreadFactoryBuilder()).setNameFormat("Netty Client IO #%d").setDaemon(true).build());
+        return 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(() -> {
-        return new EpollEventLoopGroup(0, (new ThreadFactoryBuilder()).setNameFormat("Netty Epoll Client IO #%d").setDaemon(true).build());
+        return 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(() -> {
-        return new DefaultEventLoopGroup(0, (new ThreadFactoryBuilder()).setNameFormat("Netty Local Client IO #%d").setDaemon(true).build());
+        return 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;
@@ -96,6 +96,11 @@
     private final Queue<Consumer<Connection>> pendingActions = Queues.newConcurrentLinkedQueue();
     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
@@ -114,7 +119,25 @@
     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) {
+            org.bukkit.craftbukkit.entity.CraftPlayer player = impl.getCraftPlayer();
+            return player == null ? null : player.getHandle();
+        }
+        return null;
+    }
+    // Paper end - add utility methods
+
     public Connection(PacketFlow side) {
         this.receiving = side;
     }
@@ -123,6 +146,9 @@
         super.channelActive(channelhandlercontext);
         this.channel = channelhandlercontext.channel();
         this.address = this.channel.remoteAddress();
+        // Spigot Start
+        this.preparing = false;
+        // Spigot End
         if (this.delayedDisconnect != null) {
             this.disconnect(this.delayedDisconnect);
         }
@@ -176,6 +202,7 @@
 
             }
         }
+        if (net.minecraft.server.MinecraftServer.getServer().isDebugging()) io.papermc.paper.util.TraceUtil.printStackTrace(throwable); // Spigot // Paper
     }
 
     protected void channelRead0(ChannelHandlerContext channelhandlercontext, Packet<?> packet) {
@@ -205,7 +232,7 @@
     }
 
     private static <T extends PacketListener> void genericsFtw(Packet<T> packet, PacketListener listener) {
-        packet.handle(listener);
+        packet.handle((T) listener); // CraftBukkit - decompile error
     }
 
     private void validateListener(ProtocolInfo<?> state, PacketListener listener) {
@@ -431,7 +458,7 @@
         }
 
         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) {
@@ -464,12 +491,15 @@
     }
 
     public void disconnect(DisconnectionDetails disconnectionInfo) {
+        // Spigot Start
+        this.preparing = false;
+        // Spigot End
         if (this.channel == null) {
             this.delayedDisconnect = disconnectionInfo;
         }
 
         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 = disconnectionInfo;
         }
 
@@ -537,7 +567,7 @@
     }
 
     public void configurePacketHandler(ChannelPipeline pipeline) {
-        pipeline.addLast("hackfix", new ChannelOutboundHandlerAdapter(this) {
+        pipeline.addLast("hackfix", new ChannelOutboundHandlerAdapter() { // CraftBukkit - decompile error
             public void write(ChannelHandlerContext channelhandlercontext, Object object, ChannelPromise channelpromise) throws Exception {
                 super.write(channelhandlercontext, object, channelpromise);
             }
@@ -660,7 +690,28 @@
                     });
 
                     packetlistener1.onDisconnect(disconnectiondetails);
+                }
+                this.pendingActions.clear(); // Free up packet queue.
+                // Paper start - Add PlayerConnectionCloseEvent
+                final PacketListener packetListener = this.getPacketListener();
+                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.getId(),
+                        profile.getName(), ((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.getId(), profile.getName(),
+                                ((InetSocketAddress) this.address).getAddress(), false).callEvent();
+                    }
                 }
+                // Paper end - Add PlayerConnectionCloseEvent
 
             }
         }