Several fixes and new api for experience merging/stacking (#9242)

patches/server/0769-Elder-Guardian-appearance-API.patch

@@ -0,0 +1,24 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: SoSeDiK <mrsosedik@gmail.com>
+Date: Tue, 11 Oct 2022 20:38:47 +0300
+Subject: [PATCH] Elder Guardian appearance API
+
+
+diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+index 9fd66c351dc74ed9a62db1efd58df2c5bfddfad8..d3fb8dfa57b83bcdca34909269a09787c2b5ae7b 100644
+--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
++++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+@@ -3271,6 +3271,13 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
+     }
+     // Paper end
+ 
++    // Paper start
++    @Override
++    public void showElderGuardian(boolean silent) {
++        if (getHandle().connection != null) getHandle().connection.send(new ClientboundGameEventPacket(ClientboundGameEventPacket.GUARDIAN_ELDER_EFFECT, silent ? 0F : 1F));
++    }
++    // Paper end
++
+     public Player.Spigot spigot()
+     {
+         return this.spigot;