Don't handle sync packets for kicked players

nms-patches/PlayerConnection.patch

@@ -73,7 +73,7 @@
 +    }
 +
 +    private final org.bukkit.craftbukkit.CraftServer server;
-+    private boolean processedDisconnect;
++    public boolean processedDisconnect;
 +    private int lastTick = MinecraftServer.currentTick;
 +    private int allowedPlayerTicks = 1;
 +    private int lastDropTick = MinecraftServer.currentTick;

nms-patches/PlayerConnectionUtils.patch

@@ -0,0 +1,10 @@
+--- a/net/minecraft/server/PlayerConnectionUtils.java
++++ b/net/minecraft/server/PlayerConnectionUtils.java
+@@ -5,6 +5,7 @@
+     public static <T extends PacketListener> void ensureMainThread(Packet<T> packet, T t0, IAsyncTaskHandler iasynctaskhandler) throws CancelledPacketHandleException {
+         if (!iasynctaskhandler.isMainThread()) {
+             iasynctaskhandler.postToMainThread(() -> {
++                if (t0 instanceof PlayerConnection && ((PlayerConnection) t0).processedDisconnect) return; // CraftBukkit
+                 packet.a(t0);
+             });
+             throw CancelledPacketHandleException.INSTANCE;