diff --git a/sources/src/main/java/io/akarin/api/Akari.java b/sources/src/main/java/io/akarin/api/Akari.java
index 319adea0e..f026c33d3 100644
--- a/sources/src/main/java/io/akarin/api/Akari.java
+++ b/sources/src/main/java/io/akarin/api/Akari.java
@@ -15,6 +15,7 @@ import com.google.common.util.concurrent.ThreadFactoryBuilder;
 
 import co.aikar.timings.Timing;
 import co.aikar.timings.Timings;
+import net.minecraft.server.Chunk;
 
 public abstract class Akari {
     /**
@@ -61,13 +62,15 @@ public abstract class Akari {
     /*
      * Timings
      */
-    public static Timing worldTiming = getWorldTiming();
+    public static Timing worldTiming = getTiming("Akarin - World");
     
-    private static Timing getWorldTiming() {
+    public static Timing callbackTiming = getTiming("Akarin - Callback");
+    
+    private static Timing getTiming(String name) {
         try {
             Method ofSafe = Timings.class.getDeclaredMethod("ofSafe", String.class);
             ofSafe.setAccessible(true);
-            return worldTiming = (Timing) ofSafe.invoke(null, "Akarin - World");
+            return worldTiming = (Timing) ofSafe.invoke(null, name);
         } catch (Throwable t) {
             t.printStackTrace();
             return null;
diff --git a/sources/src/main/java/io/akarin/server/mixin/core/MixinMinecraftServer.java b/sources/src/main/java/io/akarin/server/mixin/core/MixinMinecraftServer.java
index da0418daf..005971fd1 100644
--- a/sources/src/main/java/io/akarin/server/mixin/core/MixinMinecraftServer.java
+++ b/sources/src/main/java/io/akarin/server/mixin/core/MixinMinecraftServer.java
@@ -163,6 +163,10 @@ public class MixinMinecraftServer {
             }
         }
         
+        Akari.callbackTiming.startTiming();
+        while ((runnable = Akari.callbackQueue.poll()) != null) runnable.run();
+        Akari.callbackTiming.stopTiming();
+        
         for (int i = 0; i < worlds.size(); ++i) {
             WorldServer world = worlds.get(i);
             tickConflictSync(world);
diff --git a/sources/src/main/java/net/minecraft/server/ChunkRegionLoader.java b/sources/src/main/java/net/minecraft/server/ChunkRegionLoader.java
new file mode 100644
index 000000000..fa70ea2b5
--- /dev/null
+++ b/sources/src/main/java/net/minecraft/server/ChunkRegionLoader.java
@@ -0,0 +1,619 @@
+package net.minecraft.server;
+
+import com.google.common.collect.Maps;
+
+import io.akarin.api.Akari;
+
+import java.io.DataInputStream;
+import java.io.DataOutput;
+import java.io.DataOutputStream;
+import java.io.File;
+import java.io.IOException;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import javax.annotation.Nullable;
+import java.util.concurrent.ConcurrentLinkedQueue; // Paper
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+// Spigot start
+import java.util.function.Supplier;
+import org.spigotmc.SupplierUtils;
+// Spigot end
+
+public class ChunkRegionLoader implements IChunkLoader, IAsyncChunkSaver {
+
+    private ConcurrentLinkedQueue<QueuedChunk> queue = new ConcurrentLinkedQueue<>(); // Paper - Chunk queue improvements
+    private final Object lock = new Object(); // Paper - Chunk queue improvements
+    private static final Logger a = LogManager.getLogger();
+    private final Map<ChunkCoordIntPair, Supplier<NBTTagCompound>> b = Maps.newConcurrentMap(); // Spigot
+    // CraftBukkit
+    // private final Set<ChunkCoordIntPair> c = Collections.newSetFromMap(Maps.newConcurrentMap());
+    private final File d;
+    private final DataConverterManager e;
+    // private boolean f;
+    // CraftBukkit
+    private static final double SAVE_QUEUE_TARGET_SIZE = 625; // Spigot
+
+    public ChunkRegionLoader(File file, DataConverterManager dataconvertermanager) {
+        this.d = file;
+        this.e = dataconvertermanager;
+    }
+
+    // Paper start
+    private long queuedSaves = 0;
+    private final java.util.concurrent.atomic.AtomicLong processedSaves = new java.util.concurrent.atomic.AtomicLong(0L);
+    public int getQueueSize() { return queue.size(); }
+    public long getQueuedSaves() { return queuedSaves; }
+    public long getProcessedSaves() { return processedSaves.longValue(); }
+    // Paper end
+
+    // CraftBukkit start - Add async variant, provide compatibility
+    @Override
+    @Nullable
+    public Chunk a(World world, int i, int j) throws IOException {
+        world.timings.syncChunkLoadDataTimer.startTiming(); // Spigot
+        Object[] data = loadChunk(world, i, j);
+        world.timings.syncChunkLoadDataTimer.stopTiming(); // Spigot
+        if (data != null) {
+            Chunk chunk = (Chunk) data[0];
+            NBTTagCompound nbttagcompound = (NBTTagCompound) data[1];
+            loadEntities(chunk, nbttagcompound.getCompound("Level"), world);
+            return chunk;
+        }
+
+        return null;
+    }
+
+    public Object[] loadChunk(World world, int i, int j) throws IOException {
+        // CraftBukkit end
+        ChunkCoordIntPair chunkcoordintpair = new ChunkCoordIntPair(i, j);
+        NBTTagCompound nbttagcompound = SupplierUtils.getIfExists(this.b.get(chunkcoordintpair)); // Spigot
+
+        if (nbttagcompound == null) {
+            // CraftBukkit start
+            nbttagcompound = RegionFileCache.d(this.d, i, j);
+
+            if (nbttagcompound == null) {
+                return null;
+            }
+
+            nbttagcompound = this.e.a(DataConverterTypes.CHUNK, nbttagcompound);
+            // CraftBukkit end
+        }
+
+        return this.a(world, i, j, nbttagcompound);
+    }
+
+    @Override
+    public boolean chunkExists(int i, int j) {
+        ChunkCoordIntPair chunkcoordintpair = new ChunkCoordIntPair(i, j);
+        Supplier<NBTTagCompound> nbttagcompound = this.b.get(chunkcoordintpair); // Spigot
+
+        return nbttagcompound != null ? true : RegionFileCache.chunkExists(this.d, i, j);
+    }
+
+    @Nullable
+    protected Object[] a(World world, int i, int j, NBTTagCompound nbttagcompound) { // CraftBukkit - return Chunk -> Object[]
+        if (!nbttagcompound.hasKeyOfType("Level", 10)) {
+            ChunkRegionLoader.a.error("Chunk file at {},{} is missing level data, skipping", Integer.valueOf(i), Integer.valueOf(j));
+            return null;
+        } else {
+            NBTTagCompound nbttagcompound1 = nbttagcompound.getCompound("Level");
+
+            if (!nbttagcompound1.hasKeyOfType("Sections", 9)) {
+                ChunkRegionLoader.a.error("Chunk file at {},{} is missing block data, skipping", Integer.valueOf(i), Integer.valueOf(j));
+                return null;
+            } else {
+                Chunk chunk = this.a(world, nbttagcompound1);
+
+                if (!chunk.a(i, j)) {
+                    ChunkRegionLoader.a.error("Chunk file at {},{} is in the wrong location; relocating. (Expected {}, {}, got {}, {})", Integer.valueOf(i), Integer.valueOf(j), Integer.valueOf(i), Integer.valueOf(j), Integer.valueOf(chunk.locX), Integer.valueOf(chunk.locZ));
+                    nbttagcompound1.setInt("xPos", i);
+                    nbttagcompound1.setInt("zPos", j);
+
+                    // CraftBukkit start - Have to move tile entities since we don't load them at this stage
+                    NBTTagList tileEntities = nbttagcompound.getCompound("Level").getList("TileEntities", 10);
+                    if (tileEntities != null) {
+                        for (int te = 0; te < tileEntities.size(); te++) {
+                            NBTTagCompound tileEntity = tileEntities.get(te);
+                            int x = tileEntity.getInt("x") - chunk.locX * 16;
+                            int z = tileEntity.getInt("z") - chunk.locZ * 16;
+                            tileEntity.setInt("x", i * 16 + x);
+                            tileEntity.setInt("z", j * 16 + z);
+                        }
+                    }
+                    // CraftBukkit end
+                    chunk = this.a(world, nbttagcompound1);
+                }
+
+                // CraftBukkit start
+                Object[] data = new Object[2];
+                data[0] = chunk;
+                data[1] = nbttagcompound;
+                return data;
+                // CraftBukkit end
+            }
+        }
+    }
+
+    @Override
+    public void saveChunk(World world, Chunk chunk, boolean unloaded) throws IOException, ExceptionWorldConflict { // Spigot
+        world.checkSession();
+
+        try {
+            NBTTagCompound nbttagcompound = new NBTTagCompound();
+            NBTTagCompound nbttagcompound1 = new NBTTagCompound();
+
+            nbttagcompound.set("Level", nbttagcompound1);
+            nbttagcompound.setInt("DataVersion", 1343);
+
+            // Spigot start
+            final long worldTime = world.getTime();
+            final boolean worldHasSkyLight = world.worldProvider.m();
+            Akari.callbackQueue.add(() -> saveEntities(nbttagcompound1, chunk, world)); // Akarin
+            Supplier<NBTTagCompound> completion = new Supplier<NBTTagCompound>() {
+                @Override
+                public NBTTagCompound get() {
+                    saveBody(nbttagcompound1, chunk, worldTime, worldHasSkyLight);
+                    return nbttagcompound;
+                }
+            };
+
+            this.a(chunk.k(), SupplierUtils.createUnivaluedSupplier(completion, unloaded && this.b.size() < SAVE_QUEUE_TARGET_SIZE));
+            // Spigot end
+        } catch (Exception exception) {
+            ChunkRegionLoader.a.error("Failed to save chunk", exception);
+        }
+
+    }
+
+    protected void a(ChunkCoordIntPair chunkcoordintpair, Supplier<NBTTagCompound> nbttagcompound) { // Spigot
+        // CraftBukkit
+        // if (!this.c.contains(chunkcoordintpair))
+        synchronized (lock) {  // Paper - Chunk queue improvements
+            this.b.put(chunkcoordintpair, nbttagcompound);
+        }
+        queuedSaves++; // Paper
+        queue.add(new QueuedChunk(chunkcoordintpair, nbttagcompound)); // Paper - Chunk queue improvements
+
+        FileIOThread.a().a(this);
+    }
+
+    @Override
+    public boolean a() {
+        // CraftBukkit start
+        return this.processSaveQueueEntry(false);
+    }
+
+    private synchronized boolean processSaveQueueEntry(boolean logCompletion) {
+        // CraftBukkit start
+        // Paper start - Chunk queue improvements
+        QueuedChunk chunk = queue.poll();
+        if (chunk == null) {
+        // Paper - end
+            if (logCompletion) {
+                // CraftBukkit end
+                ChunkRegionLoader.a.info("ThreadedAnvilChunkStorage ({}): All chunks are saved", this.d.getName());
+            }
+
+            return false;
+        } else {
+            ChunkCoordIntPair chunkcoordintpair = chunk.coords; // Paper - Chunk queue improvements
+            processedSaves.incrementAndGet(); // Paper
+
+            boolean flag;
+
+            try {
+                // this.c.add(chunkcoordintpair);
+                NBTTagCompound nbttagcompound = SupplierUtils.getIfExists(chunk.compoundSupplier); // Spigot // Paper
+                // CraftBukkit
+
+                if (nbttagcompound != null) {
+                    int attempts = 0; Exception laste = null; while (attempts++ < 5) { // Paper
+                    try {
+                        this.b(chunkcoordintpair, nbttagcompound);
+                        laste = null; break; // Paper
+                    } catch (Exception exception) {
+                        //ChunkRegionLoader.a.error("Failed to save chunk", exception); // Paper
+                        laste = exception; // Paper
+                    }
+                    try {Thread.sleep(10);} catch (InterruptedException e) {e.printStackTrace();} } // Paper
+                    if (laste != null) { com.destroystokyo.paper.exception.ServerInternalException.reportInternalException(laste); MinecraftServer.LOGGER.error("Failed to save chunk", laste); } // Paper
+                }
+                synchronized (lock) { if (this.b.get(chunkcoordintpair) == chunk.compoundSupplier) { this.b.remove(chunkcoordintpair); } }// Paper - This will not equal if a newer version is still pending
+
+                flag = true;
+            } finally {
+                //this.b.remove(chunkcoordintpair, value); // CraftBukkit // Spigot // Paper
+            }
+
+            return flag;
+        }
+    }
+
+    private void b(ChunkCoordIntPair chunkcoordintpair, NBTTagCompound nbttagcompound) throws IOException {
+        // CraftBukkit start
+        RegionFileCache.e(this.d, chunkcoordintpair.x, chunkcoordintpair.z, nbttagcompound);
+
+        /*
+        NBTCompressedStreamTools.a(nbttagcompound, (DataOutput) dataoutputstream);
+        dataoutputstream.close();
+        */
+        // CraftBukkit end
+    }
+
+    public void b(World world, Chunk chunk) throws IOException {}
+
+    @Override
+    public void b() {}
+
+    @Override
+    public void c() {
+        try {
+            // this.f = true; // CraftBukkit
+
+            while (true) {
+                if (this.processSaveQueueEntry(true)) { // CraftBukkit
+                    continue;
+                }
+                break; // CraftBukkit - Fix infinite loop when saving chunks
+            }
+        } finally {
+            // this.f = false; // CraftBukkit
+        }
+
+    }
+
+    public static void a(DataConverterManager dataconvertermanager) {
+        dataconvertermanager.a(DataConverterTypes.CHUNK, new DataInspector() {
+            @Override
+            public NBTTagCompound a(DataConverter dataconverter, NBTTagCompound nbttagcompound, int i) {
+                if (nbttagcompound.hasKeyOfType("Level", 10)) {
+                    NBTTagCompound nbttagcompound1 = nbttagcompound.getCompound("Level");
+                    NBTTagList nbttaglist;
+                    int j;
+
+                    if (nbttagcompound1.hasKeyOfType("Entities", 9)) {
+                        nbttaglist = nbttagcompound1.getList("Entities", 10);
+
+                        for (j = 0; j < nbttaglist.size(); ++j) {
+                            nbttaglist.a(j, dataconverter.a(DataConverterTypes.ENTITY, (NBTTagCompound) nbttaglist.i(j), i));
+                        }
+                    }
+
+                    if (nbttagcompound1.hasKeyOfType("TileEntities", 9)) {
+                        nbttaglist = nbttagcompound1.getList("TileEntities", 10);
+
+                        for (j = 0; j < nbttaglist.size(); ++j) {
+                            nbttaglist.a(j, dataconverter.a(DataConverterTypes.BLOCK_ENTITY, (NBTTagCompound) nbttaglist.i(j), i));
+                        }
+                    }
+                }
+
+                return nbttagcompound;
+            }
+        });
+    }
+
+    private static void saveBody(NBTTagCompound nbttagcompound, Chunk chunk, long worldTime, boolean worldHasSkyLight) { // Spigot
+        nbttagcompound.setInt("xPos", chunk.locX);
+        nbttagcompound.setInt("zPos", chunk.locZ);
+        nbttagcompound.setLong("LastUpdate", worldTime); // Spigot
+        nbttagcompound.setIntArray("HeightMap", chunk.r());
+        nbttagcompound.setBoolean("TerrainPopulated", chunk.isDone());
+        nbttagcompound.setBoolean("LightPopulated", chunk.v());
+        nbttagcompound.setLong("InhabitedTime", chunk.x());
+        ChunkSection[] achunksection = chunk.getSections();
+        NBTTagList nbttaglist = new NBTTagList();
+        boolean flag = worldHasSkyLight; // Spigot
+        ChunkSection[] achunksection1 = achunksection;
+        int i = achunksection.length;
+
+        NBTTagCompound nbttagcompound1;
+
+        for (int j = 0; j < i; ++j) {
+            ChunkSection chunksection = achunksection1[j];
+
+            if (chunksection != Chunk.a) {
+                nbttagcompound1 = new NBTTagCompound();
+                nbttagcompound1.setByte("Y", (byte) (chunksection.getYPosition() >> 4 & 255));
+                byte[] abyte = new byte[4096];
+                NibbleArray nibblearray = new NibbleArray();
+                NibbleArray nibblearray1 = chunksection.getBlocks().exportData(abyte, nibblearray);
+
+                nbttagcompound1.setByteArray("Blocks", abyte);
+                nbttagcompound1.setByteArray("Data", nibblearray.asBytes());
+                if (nibblearray1 != null) {
+                    nbttagcompound1.setByteArray("Add", nibblearray1.asBytes());
+                }
+
+                nbttagcompound1.setByteArray("BlockLight", chunksection.getEmittedLightArray().asBytes());
+                if (flag) {
+                    nbttagcompound1.setByteArray("SkyLight", chunksection.getSkyLightArray().asBytes());
+                } else {
+                    nbttagcompound1.setByteArray("SkyLight", new byte[chunksection.getEmittedLightArray().asBytes().length]);
+                }
+
+                nbttaglist.add(nbttagcompound1);
+            }
+        }
+
+        nbttagcompound.set("Sections", nbttaglist);
+        nbttagcompound.setByteArray("Biomes", chunk.getBiomeIndex());
+
+        // Spigot start - End this method here and split off entity saving to another method
+    }
+
+    private static void saveEntities(NBTTagCompound nbttagcompound, Chunk chunk, World world) {
+        int i;
+        NBTTagCompound nbttagcompound1;
+        // Spigot end
+
+        chunk.g(false);
+        NBTTagList nbttaglist1 = new NBTTagList();
+
+        Iterator iterator;
+
+        for (i = 0; i < chunk.getEntitySlices().length; ++i) {
+            iterator = chunk.getEntitySlices()[i].iterator();
+
+            while (iterator.hasNext()) {
+                Entity entity = (Entity) iterator.next();
+
+                nbttagcompound1 = new NBTTagCompound();
+                if (entity.d(nbttagcompound1)) {
+                    chunk.g(true);
+                    nbttaglist1.add(nbttagcompound1);
+                }
+            }
+        }
+
+        nbttagcompound.set("Entities", nbttaglist1);
+        NBTTagList nbttaglist2 = new NBTTagList();
+
+        iterator = chunk.getTileEntities().values().iterator();
+
+        while (iterator.hasNext()) {
+            TileEntity tileentity = (TileEntity) iterator.next();
+
+            nbttagcompound1 = tileentity.save(new NBTTagCompound());
+            nbttaglist2.add(nbttagcompound1);
+        }
+
+        nbttagcompound.set("TileEntities", nbttaglist2);
+        List list = world.a(chunk, false);
+
+        if (list != null) {
+            long k = world.getTime();
+            NBTTagList nbttaglist3 = new NBTTagList();
+            Iterator iterator1 = list.iterator();
+
+            while (iterator1.hasNext()) {
+                NextTickListEntry nextticklistentry = (NextTickListEntry) iterator1.next();
+                NBTTagCompound nbttagcompound2 = new NBTTagCompound();
+                MinecraftKey minecraftkey = Block.REGISTRY.b(nextticklistentry.a());
+
+                nbttagcompound2.setString("i", minecraftkey == null ? "" : minecraftkey.toString());
+                nbttagcompound2.setInt("x", nextticklistentry.a.getX());
+                nbttagcompound2.setInt("y", nextticklistentry.a.getY());
+                nbttagcompound2.setInt("z", nextticklistentry.a.getZ());
+                nbttagcompound2.setInt("t", (int) (nextticklistentry.b - k));
+                nbttagcompound2.setInt("p", nextticklistentry.c);
+                nbttaglist3.add(nbttagcompound2);
+            }
+
+            nbttagcompound.set("TileTicks", nbttaglist3);
+        }
+
+    }
+
+    private Chunk a(World world, NBTTagCompound nbttagcompound) {
+        int i = nbttagcompound.getInt("xPos");
+        int j = nbttagcompound.getInt("zPos");
+        Chunk chunk = new Chunk(world, i, j);
+
+        chunk.a(nbttagcompound.getIntArray("HeightMap"));
+        chunk.d(nbttagcompound.getBoolean("TerrainPopulated"));
+        chunk.e(nbttagcompound.getBoolean("LightPopulated"));
+        chunk.c(nbttagcompound.getLong("InhabitedTime"));
+        NBTTagList nbttaglist = nbttagcompound.getList("Sections", 10);
+        boolean flag = true;
+        ChunkSection[] achunksection = new ChunkSection[16];
+        boolean flag1 = world.worldProvider.m();
+
+        for (int k = 0; k < nbttaglist.size(); ++k) {
+            NBTTagCompound nbttagcompound1 = nbttaglist.get(k);
+            byte b0 = nbttagcompound1.getByte("Y");
+            ChunkSection chunksection = new ChunkSection(b0 << 4, flag1, world.chunkPacketBlockController.getPredefinedBlockData(chunk, b0)); // Paper - Anti-Xray - Add predefined block data
+            byte[] abyte = nbttagcompound1.getByteArray("Blocks");
+            NibbleArray nibblearray = new NibbleArray(nbttagcompound1.getByteArray("Data"));
+            NibbleArray nibblearray1 = nbttagcompound1.hasKeyOfType("Add", 7) ? new NibbleArray(nbttagcompound1.getByteArray("Add")) : null;
+
+            chunksection.getBlocks().a(abyte, nibblearray, nibblearray1);
+            chunksection.a(new NibbleArray(nbttagcompound1.getByteArray("BlockLight")));
+            if (flag1) {
+                chunksection.b(new NibbleArray(nbttagcompound1.getByteArray("SkyLight")));
+            }
+
+            chunksection.recalcBlockCounts();
+            achunksection[b0] = chunksection;
+        }
+
+        chunk.a(achunksection);
+        if (nbttagcompound.hasKeyOfType("Biomes", 7)) {
+            chunk.a(nbttagcompound.getByteArray("Biomes"));
+        }
+
+        // CraftBukkit start - End this method here and split off entity loading to another method
+        return chunk;
+    }
+
+    public void loadEntities(Chunk chunk, NBTTagCompound nbttagcompound, World world) {
+        // CraftBukkit end
+        world.timings.syncChunkLoadNBTTimer.startTiming(); // Spigot
+        NBTTagList nbttaglist1 = nbttagcompound.getList("Entities", 10);
+
+        for (int l = 0; l < nbttaglist1.size(); ++l) {
+            NBTTagCompound nbttagcompound2 = nbttaglist1.get(l);
+
+            a(nbttagcompound2, world, chunk);
+            chunk.g(true);
+        }
+        NBTTagList nbttaglist2 = nbttagcompound.getList("TileEntities", 10);
+
+        for (int i1 = 0; i1 < nbttaglist2.size(); ++i1) {
+            NBTTagCompound nbttagcompound3 = nbttaglist2.get(i1);
+            TileEntity tileentity = TileEntity.create(world, nbttagcompound3);
+
+            if (tileentity != null) {
+                chunk.a(tileentity);
+            }
+        }
+
+        if (nbttagcompound.hasKeyOfType("TileTicks", 9)) {
+            NBTTagList nbttaglist3 = nbttagcompound.getList("TileTicks", 10);
+
+            for (int j1 = 0; j1 < nbttaglist3.size(); ++j1) {
+                NBTTagCompound nbttagcompound4 = nbttaglist3.get(j1);
+                Block block;
+
+                if (nbttagcompound4.hasKeyOfType("i", 8)) {
+                    block = Block.getByName(nbttagcompound4.getString("i"));
+                } else {
+                    block = Block.getById(nbttagcompound4.getInt("i"));
+                }
+
+                world.b(new BlockPosition(nbttagcompound4.getInt("x"), nbttagcompound4.getInt("y"), nbttagcompound4.getInt("z")), block, nbttagcompound4.getInt("t"), nbttagcompound4.getInt("p"));
+            }
+        }
+        world.timings.syncChunkLoadNBTTimer.stopTiming(); // Spigot
+
+        // return chunk; // CraftBukkit
+    }
+
+    @Nullable
+    public static Entity a(NBTTagCompound nbttagcompound, World world, Chunk chunk) {
+        Entity entity = a(nbttagcompound, world);
+
+        if (entity == null) {
+            return null;
+        } else {
+            chunk.a(entity);
+            if (nbttagcompound.hasKeyOfType("Passengers", 9)) {
+                NBTTagList nbttaglist = nbttagcompound.getList("Passengers", 10);
+
+                for (int i = 0; i < nbttaglist.size(); ++i) {
+                    Entity entity1 = a(nbttaglist.get(i), world, chunk);
+
+                    if (entity1 != null) {
+                        entity1.a(entity, true);
+                    }
+                }
+            }
+
+            return entity;
+        }
+    }
+
+    @Nullable
+    // CraftBukkit start
+    public static Entity a(NBTTagCompound nbttagcompound, World world, double d0, double d1, double d2, boolean flag) {
+        return spawnEntity(nbttagcompound, world, d0, d1, d2, flag, org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.DEFAULT);
+    }
+
+    public static Entity spawnEntity(NBTTagCompound nbttagcompound, World world, double d0, double d1, double d2, boolean flag, org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason spawnReason) {
+        // CraftBukkit end
+        Entity entity = a(nbttagcompound, world);
+
+        if (entity == null) {
+            return null;
+        } else {
+            entity.setPositionRotation(d0, d1, d2, entity.yaw, entity.pitch);
+            if (flag && !world.addEntity(entity, spawnReason)) { // CraftBukkit
+                return null;
+            } else {
+                if (nbttagcompound.hasKeyOfType("Passengers", 9)) {
+                    NBTTagList nbttaglist = nbttagcompound.getList("Passengers", 10);
+
+                    for (int i = 0; i < nbttaglist.size(); ++i) {
+                        Entity entity1 = a(nbttaglist.get(i), world, d0, d1, d2, flag);
+
+                        if (entity1 != null) {
+                            entity1.a(entity, true);
+                        }
+                    }
+                }
+
+                return entity;
+            }
+        }
+    }
+
+    @Nullable
+    protected static Entity a(NBTTagCompound nbttagcompound, World world) {
+        try {
+            return EntityTypes.a(nbttagcompound, world);
+        } catch (RuntimeException runtimeexception) {
+            return null;
+        }
+    }
+
+    // CraftBukkit start
+    public static void a(Entity entity, World world) {
+        a(entity, world, org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.DEFAULT);
+    }
+
+    public static void a(Entity entity, World world, org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason reason) {
+        if (!entity.valid && world.addEntity(entity, reason) && entity.isVehicle()) { // Paper
+            // CraftBukkit end
+            Iterator iterator = entity.bF().iterator();
+
+            while (iterator.hasNext()) {
+                Entity entity1 = (Entity) iterator.next();
+
+                a(entity1, world);
+            }
+        }
+
+    }
+
+    @Nullable
+    public static Entity a(NBTTagCompound nbttagcompound, World world, boolean flag) {
+        Entity entity = a(nbttagcompound, world);
+
+        if (entity == null) {
+            return null;
+        } else if (flag && !world.addEntity(entity)) {
+            return null;
+        } else {
+            if (nbttagcompound.hasKeyOfType("Passengers", 9)) {
+                NBTTagList nbttaglist = nbttagcompound.getList("Passengers", 10);
+
+                for (int i = 0; i < nbttaglist.size(); ++i) {
+                    Entity entity1 = a(nbttaglist.get(i), world, flag);
+
+                    if (entity1 != null) {
+                        entity1.a(entity, true);
+                    }
+                }
+            }
+
+            return entity;
+        }
+    }
+
+    // Paper start - Chunk queue improvements
+    private static class QueuedChunk {
+        public ChunkCoordIntPair coords;
+        public Supplier<NBTTagCompound> compoundSupplier;
+
+        public QueuedChunk(ChunkCoordIntPair coords, Supplier<NBTTagCompound> compoundSupplier) {
+            this.coords = coords;
+            this.compoundSupplier = compoundSupplier;
+        }
+    }
+    // Paper end
+}