port Significantly improve performance of the end generation (#7919)

patches/server/0651-Attributes-API-for-item-defaults.patch

@@ -0,0 +1,30 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Jake Potrebic <jake.m.potrebic@gmail.com>
+Date: Sat, 8 May 2021 15:01:54 -0700
+Subject: [PATCH] Attributes API for item defaults
+
+
+diff --git a/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java b/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
+index 57b7fedcccbb9a0c1cc56eb6be48a18e2fbadc7f..5345ab40f18437fc60080f9feff4ee0d59a9ed6d 100644
+--- a/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
++++ b/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
+@@ -545,6 +545,19 @@ public final class CraftMagicNumbers implements UnsafeValues {
+         return CraftMagicNumbers.getItem(itemToBeRepaired.getType()).isValidRepairItem(CraftItemStack.asNMSCopy(itemToBeRepaired), CraftItemStack.asNMSCopy(repairMaterial));
+     }
+ 
++    @Override
++    public Multimap<Attribute, AttributeModifier> getItemAttributes(Material material, EquipmentSlot equipmentSlot) {
++        Item item = CraftMagicNumbers.getItem(material);
++        if (item == null) {
++            throw new IllegalArgumentException(material + " is not an item and therefore does not have attributes");
++        }
++        ImmutableMultimap.Builder<Attribute, AttributeModifier> attributeMapBuilder = ImmutableMultimap.builder();
++        item.getDefaultAttributeModifiers(CraftEquipmentSlot.getNMS(equipmentSlot)).forEach((attributeBase, attributeModifier) -> {
++            attributeMapBuilder.put(CraftAttributeMap.fromMinecraft(net.minecraft.core.Registry.ATTRIBUTE.getKey(attributeBase).toString()), CraftAttributeInstance.convert(attributeModifier, equipmentSlot));
++        });
++        return attributeMapBuilder.build();
++    }
++
+     @Override
+     public int getProtocolVersion() {
+         return net.minecraft.SharedConstants.getCurrentVersion().getProtocolVersion();