Fix various World chunk methods

- Add thread check for loadChunk
- Make isChunkGenerated use the region task queue to schedule
  to "main"
- Don't complete async chunk future if not in the owning thread
  for the chunk

patches/server/0004-Threaded-Regions.patch

@@ -21859,7 +21859,7 @@ index 2ea3778ee1348e5d06b15a2c5dc5d9bd4136dbe3..72a8e27c5ff6063d2e2b3590390b24a1
  
      @Override
 diff --git a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
-index d33476ffa49d7f6388bb227f8a57cf115a74698f..ddb59118551449b4c8855cdeaabedb08af148fff 100644
+index d33476ffa49d7f6388bb227f8a57cf115a74698f..673b5dabaf3b22ea6cd31591027efc0118a44947 100644
 --- a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
 +++ b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
 @@ -180,7 +180,7 @@ public class CraftWorld extends CraftRegionAccessor implements World {
@@ -21871,7 +21871,28 @@ index d33476ffa49d7f6388bb227f8a57cf115a74698f..ddb59118551449b4c8855cdeaabedb08
      }
  
      @Override
-@@ -788,13 +788,14 @@ public class CraftWorld extends CraftRegionAccessor implements World {
+@@ -361,10 +361,10 @@ public class CraftWorld extends CraftRegionAccessor implements World {
+     @Override
+     public boolean isChunkGenerated(int x, int z) {
+         // Paper start - Fix this method
+-        if (!Bukkit.isPrimaryThread()) {
++        if (!io.papermc.paper.util.TickThread.isTickThreadFor(this.getHandle(), x, z)) { // Folia - region threading
+             return java.util.concurrent.CompletableFuture.supplyAsync(() -> {
+                 return CraftWorld.this.isChunkGenerated(x, z);
+-            }, world.getChunkSource().mainThreadProcessor).join();
++            }, (run) -> { io.papermc.paper.threadedregions.RegionisedServer.getInstance().taskQueue.queueChunkTask(this.getHandle(), x, z, run);}).join(); // Folia - region threading
+         }
+         ChunkAccess chunk = world.getChunkSource().getChunkAtImmediately(x, z);
+         if (chunk == null) {
+@@ -530,6 +530,7 @@ public class CraftWorld extends CraftRegionAccessor implements World {
+ 
+     @Override
+     public boolean loadChunk(int x, int z, boolean generate) {
++        io.papermc.paper.util.TickThread.ensureTickThread(this.getHandle(), x, z, "May not sync load chunks asynchronously"); // Folia - region threading
+         org.spigotmc.AsyncCatcher.catchOp("chunk load"); // Spigot
+         warnUnsafeChunk("loading a faraway chunk", x, z); // Paper
+         // Paper start - Optimize this method
+@@ -788,13 +789,14 @@ public class CraftWorld extends CraftRegionAccessor implements World {
  
      @Override
      public boolean generateTree(Location loc, TreeType type, BlockChangeDelegate delegate) {
@@ -21891,7 +21912,7 @@ index d33476ffa49d7f6388bb227f8a57cf115a74698f..ddb59118551449b4c8855cdeaabedb08
                  BlockPos position = ((CraftBlockState) blockstate).getPosition();
                  net.minecraft.world.level.block.state.BlockState oldBlock = this.world.getBlockState(position);
                  int flag = ((CraftBlockState) blockstate).getFlag();
-@@ -802,10 +803,10 @@ public class CraftWorld extends CraftRegionAccessor implements World {
+@@ -802,10 +804,10 @@ public class CraftWorld extends CraftRegionAccessor implements World {
                  net.minecraft.world.level.block.state.BlockState newBlock = this.world.getBlockState(position);
                  this.world.notifyAndUpdatePhysics(position, null, oldBlock, newBlock, newBlock, flag, 512);
              }
@@ -21904,7 +21925,7 @@ index d33476ffa49d7f6388bb227f8a57cf115a74698f..ddb59118551449b4c8855cdeaabedb08
              return false;
          }
      }
-@@ -878,7 +879,7 @@ public class CraftWorld extends CraftRegionAccessor implements World {
+@@ -878,7 +880,7 @@ public class CraftWorld extends CraftRegionAccessor implements World {
  
      @Override
      public long getGameTime() {
@@ -21913,7 +21934,7 @@ index d33476ffa49d7f6388bb227f8a57cf115a74698f..ddb59118551449b4c8855cdeaabedb08
      }
  
      @Override
-@@ -1853,7 +1854,7 @@ public class CraftWorld extends CraftRegionAccessor implements World {
+@@ -1853,7 +1855,7 @@ public class CraftWorld extends CraftRegionAccessor implements World {
          if (!(entity instanceof CraftEntity craftEntity) || entity.getWorld() != this || sound == null || category == null) return;
  
          ClientboundSoundEntityPacket packet = new ClientboundSoundEntityPacket(BuiltInRegistries.SOUND_EVENT.wrapAsHolder(CraftSound.getSoundEffect(sound)), net.minecraft.sounds.SoundSource.valueOf(category.name()), craftEntity.getHandle(), volume, pitch, this.getHandle().getRandom().nextLong());
@@ -21922,7 +21943,16 @@ index d33476ffa49d7f6388bb227f8a57cf115a74698f..ddb59118551449b4c8855cdeaabedb08
          if (entityTracker != null) {
              entityTracker.broadcastAndSend(packet);
          }
-@@ -2356,7 +2357,7 @@ public class CraftWorld extends CraftRegionAccessor implements World {
+@@ -2339,7 +2341,7 @@ public class CraftWorld extends CraftRegionAccessor implements World {
+     // Paper start
+     public java.util.concurrent.CompletableFuture<Chunk> getChunkAtAsync(int x, int z, boolean gen, boolean urgent) {
+         warnUnsafeChunk("getting a faraway chunk async", x, z); // Paper
+-        if (Bukkit.isPrimaryThread()) {
++        if (io.papermc.paper.util.TickThread.isTickThreadFor(this.getHandle(), x, z)) { // Folia - region threading
+             net.minecraft.world.level.chunk.LevelChunk immediate = this.world.getChunkSource().getChunkAtIfLoadedImmediately(x, z);
+             if (immediate != null) {
+                 return java.util.concurrent.CompletableFuture.completedFuture(immediate.getBukkitChunk());
+@@ -2356,7 +2358,7 @@ public class CraftWorld extends CraftRegionAccessor implements World {
          java.util.concurrent.CompletableFuture<Chunk> ret = new java.util.concurrent.CompletableFuture<>();
  
          io.papermc.paper.chunk.system.ChunkSystem.scheduleChunkLoad(this.getHandle(), x, z, gen, ChunkStatus.FULL, true, priority, (c) -> {