Prepare for updating server patches

patches/unapplied/server/Use-hash-table-for-maintaing-changed-block-set.patch

@@ -0,0 +1,30 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Spottedleaf <Spottedleaf@users.noreply.github.com>
+Date: Thu, 11 Mar 2021 21:17:02 -0800
+Subject: [PATCH] Use hash table for maintaing changed block set
+
+When a lot of block changes occur the iteration for checking can
+add up a bit and cause a small performance impact.
+
+diff --git a/src/main/java/net/minecraft/server/level/ChunkHolder.java b/src/main/java/net/minecraft/server/level/ChunkHolder.java
+index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
+--- a/src/main/java/net/minecraft/server/level/ChunkHolder.java
++++ b/src/main/java/net/minecraft/server/level/ChunkHolder.java
+@@ -0,0 +0,0 @@ import net.minecraft.world.level.lighting.LevelLightEngine;
+ import net.minecraft.server.MinecraftServer;
+ // CraftBukkit end
+ 
++import it.unimi.dsi.fastutil.shorts.ShortOpenHashSet; // Paper
++
+ public class ChunkHolder {
+ 
+     public static final Either<ChunkAccess, ChunkHolder.ChunkLoadingFailure> UNLOADED_CHUNK = Either.right(ChunkHolder.ChunkLoadingFailure.UNLOADED);
+@@ -0,0 +0,0 @@ public class ChunkHolder {
+             if (i < 0 || i >= this.changedBlocksPerSection.length) return; // CraftBukkit - SPIGOT-6086, SPIGOT-6296
+             if (this.changedBlocksPerSection[i] == null) {
+                 this.hasChangedSections = true;
+-                this.changedBlocksPerSection[i] = new ShortArraySet();
++                this.changedBlocksPerSection[i] = new ShortOpenHashSet(); // Paper - use a set to make setting constant-time
+             }
+ 
+             this.changedBlocksPerSection[i].add(SectionPos.sectionRelativePos(pos));