Actually write to the tracker field on entity

perhaps we can also look into removing this modification altogether

Spigot-Server-Patches/0105-Optional-TNT-doesn-t-move-in-water.patch

@@ -1,4 +1,4 @@
-From ff6b987910bf028eaeab7c4ed38bd9e7ee35e319 Mon Sep 17 00:00:00 2001
+From 530d6b6635e21f94b2334b735f3c773ce70a947c Mon Sep 17 00:00:00 2001
 From: Zach Brown <zach.brown@destroystokyo.com>
 Date: Sun, 22 May 2016 20:20:55 -0500
 Subject: [PATCH] Optional TNT doesn't move in water
@@ -71,7 +71,7 @@ index 2f4e56fc56..2f1cd47619 100644
      }
  
 diff --git a/src/main/java/net/minecraft/server/EntityTNTPrimed.java b/src/main/java/net/minecraft/server/EntityTNTPrimed.java
-index e0535604b6..479b62d665 100644
+index e0535604b6..723ed45d5e 100644
 --- a/src/main/java/net/minecraft/server/EntityTNTPrimed.java
 +++ b/src/main/java/net/minecraft/server/EntityTNTPrimed.java
 @@ -149,4 +149,50 @@ public class EntityTNTPrimed extends Entity {
@@ -107,7 +107,7 @@ index e0535604b6..479b62d665 100644
 +        if (this.inWater) {
 +            // Send position and velocity updates to nearby players on every tick while the TNT is in water.
 +            // This does pretty well at keeping their clients in sync with the server.
-+            EntityTrackerEntry ete = this.tracker; // TODO review this (this field isn't written to)
++            PlayerChunkMap.EntityTracker ete = this.tracker; // TODO review this (this field isn't written to)
 +            if (ete != null) {
 +                PacketPlayOutEntityVelocity velocityPacket = new PacketPlayOutEntityVelocity(this);
 +                PacketPlayOutEntityTeleport positionPacket = new PacketPlayOutEntityTeleport(this);

Spigot-Server-Patches/0258-Add-Debug-Entities-option-to-debug-dupe-uuid-issues.patch

@@ -1,4 +1,4 @@
-From 29e2b7d741c5bf7cc70114c2dc52d60f41eaed8b Mon Sep 17 00:00:00 2001
+From 1692805bdb3cb7f5ede09255253d2fd08dc16a9e Mon Sep 17 00:00:00 2001
 From: Aikar <aikar@aikar.co>
 Date: Sat, 21 Jul 2018 08:25:40 -0400
 Subject: [PATCH] Add Debug Entities option to debug dupe uuid issues
@@ -6,20 +6,41 @@ Subject: [PATCH] Add Debug Entities option to debug dupe uuid issues
 Add -Ddebug.entities=true to your JVM flags to gain more information
 
 diff --git a/src/main/java/net/minecraft/server/Entity.java b/src/main/java/net/minecraft/server/Entity.java
-index 0088d6088a..56adea9cf4 100644
+index 0088d6088a..4a42b7c594 100644
 --- a/src/main/java/net/minecraft/server/Entity.java
 +++ b/src/main/java/net/minecraft/server/Entity.java
 @@ -75,6 +75,8 @@ public abstract class Entity implements INamableTileEntity, ICommandListener, Ke
      public com.destroystokyo.paper.loottable.PaperLootableInventoryData lootableData; // Paper
      protected CraftEntity bukkitEntity;
  
-+    EntityTrackerEntry tracker; // Paper
++    PlayerChunkMap.EntityTracker tracker; // Paper
 +    Throwable addedToWorldStack; // Paper - entity debug
      public CraftEntity getBukkitEntity() {
          if (bukkitEntity == null) {
              bukkitEntity = CraftEntity.getEntity(world.getServer(), this);
+diff --git a/src/main/java/net/minecraft/server/PlayerChunkMap.java b/src/main/java/net/minecraft/server/PlayerChunkMap.java
+index eee03e39b1..96f814af3c 100644
+--- a/src/main/java/net/minecraft/server/PlayerChunkMap.java
++++ b/src/main/java/net/minecraft/server/PlayerChunkMap.java
+@@ -837,6 +837,7 @@ public class PlayerChunkMap extends IChunkLoader implements PlayerChunk.d {
+                 } else {
+                     PlayerChunkMap.EntityTracker playerchunkmap_entitytracker = new PlayerChunkMap.EntityTracker(entity, i, j, entitytypes.isDeltaTracking());
+ 
++                    entity.tracker = playerchunkmap_entitytracker; // Paper - Fast access to tracker
+                     this.trackedEntities.put(entity.getId(), playerchunkmap_entitytracker);
+                     playerchunkmap_entitytracker.track(this.world.getPlayers());
+                     if (entity instanceof EntityPlayer) {
+@@ -879,7 +880,7 @@ public class PlayerChunkMap extends IChunkLoader implements PlayerChunk.d {
+         if (playerchunkmap_entitytracker1 != null) {
+             playerchunkmap_entitytracker1.a();
+         }
+-
++        entity.tracker = null; // Paper - We're no longer tracked
+     }
+ 
+     protected void g() {
 diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
-index 2f79f9e947..f8c382cb69 100644
+index 5349a3a8bc..a7e24ed725 100644
 --- a/src/main/java/net/minecraft/server/World.java
 +++ b/src/main/java/net/minecraft/server/World.java
 @@ -68,6 +68,7 @@ public abstract class World implements IIBlockAccess, GeneratorAccess, AutoClose
@@ -31,7 +52,7 @@ index 2f79f9e947..f8c382cb69 100644
      public boolean captureBlockStates = false;
      public boolean captureTreeGeneration = false;
 diff --git a/src/main/java/net/minecraft/server/WorldServer.java b/src/main/java/net/minecraft/server/WorldServer.java
-index 1ac79158c1..8515794059 100644
+index e787faed08..08617318a9 100644
 --- a/src/main/java/net/minecraft/server/WorldServer.java
 +++ b/src/main/java/net/minecraft/server/WorldServer.java
 @@ -77,6 +77,9 @@ public class WorldServer extends World {