Add Plugin Chunk Ticket API

Allows plugins to force certain chunks to be kept loaded for as long as they are enabled.

By: Spottedleaf <Spottedleaf@users.noreply.github.com>

paper-server/src/main/java/org/bukkit/craftbukkit/CraftChunk.java

@@ -3,6 +3,7 @@ package org.bukkit.craftbukkit;
 import com.google.common.base.Preconditions;
 import java.lang.ref.WeakReference;
 import java.util.Arrays;
+import java.util.Collection;
 import net.minecraft.server.BiomeBase;
 import net.minecraft.server.BlockPosition;
 import net.minecraft.server.Blocks;
@@ -27,6 +28,7 @@ import org.bukkit.block.BlockState;
 import org.bukkit.craftbukkit.block.CraftBlock;
 import org.bukkit.craftbukkit.util.CraftMagicNumbers;
 import org.bukkit.entity.Entity;
+import org.bukkit.plugin.Plugin;
 
 public class CraftChunk implements Chunk {
     private WeakReference<net.minecraft.server.Chunk> weakChunk;
@@ -182,6 +184,21 @@ public class CraftChunk implements Chunk {
         getWorld().setChunkForceLoaded(getX(), getZ(), forced);
     }
 
+    @Override
+    public boolean addPluginChunkTicket(Plugin plugin) {
+        return getWorld().addPluginChunkTicket(getX(), getZ(), plugin);
+    }
+
+    @Override
+    public boolean removePluginChunkTicket(Plugin plugin) {
+        return getWorld().removePluginChunkTicket(getX(), getZ(), plugin);
+    }
+
+    @Override
+    public Collection<Plugin> getPluginChunkTickets() {
+        return getWorld().getPluginChunkTickets(getX(), getZ());
+    }
+
     @Override
     public ChunkSnapshot getChunkSnapshot() {
         return getChunkSnapshot(true, false, false);