Add AnvilChunkLoader to reducing allocations of MutableChunkCoordIntPair

src/main/java/com/mitchej123/hodgepodge/mixins/Mixins.java

@@ -29,7 +29,8 @@ public enum Mixins {
                     .addMixinClasses(
                             "minecraft.MixinChunkCoordIntPair",
                             "minecraft.MixinWorld_FixAllocations",
-                            "minecraft.MixinWorldClient_FixAllocations")
+                            "minecraft.MixinWorldClient_FixAllocations",
+                            "minecraft.MixinAnvilChunkLoader_FixAllocations")
                     .setApplyIf(() -> FixesConfig.fixTooManyAllocationsChunkPositionIntPair)),
     FIX_TOO_MANY_ALLOCATIONS_CHUNK_POSITION_INT_PAIR_OPTIFINE_INCOMPAT(
             new Builder("Stops MC from allocating too many ChunkPositionIntPair objects")

src/main/java/com/mitchej123/hodgepodge/mixins/early/minecraft/MixinAnvilChunkLoader_FixAllocations.java

@@ -0,0 +1,28 @@
+package com.mitchej123.hodgepodge.mixins.early.minecraft;
+
+import java.util.Set;
+
+import net.minecraft.world.ChunkCoordIntPair;
+import net.minecraft.world.chunk.storage.AnvilChunkLoader;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Redirect;
+
+import com.mitchej123.hodgepodge.hax.LongChunkCoordIntPairSet;
+import com.mitchej123.hodgepodge.mixins.interfaces.MutableChunkCoordIntPair;
+
+@Mixin(AnvilChunkLoader.class)
+public class MixinAnvilChunkLoader_FixAllocations {
+
+    @Shadow
+    private Set<ChunkCoordIntPair> pendingAnvilChunksCoordinates = new LongChunkCoordIntPairSet();
+
+    private final MutableChunkCoordIntPair reusableCCIP = (MutableChunkCoordIntPair) new ChunkCoordIntPair(0, 0);
+
+    @Redirect(method = "chunkExists", at = @At(value = "NEW", target = "Lnet/minecraft/world/ChunkCoordIntPair;"))
+    private ChunkCoordIntPair chunkExistsReusable(int i, int j) {
+        return (ChunkCoordIntPair) reusableCCIP.setChunkPos(i, j);
+    }
+}