Optimise IEntityAccess#getPlayerByUUID (#2842)

Use the world entity map instead of iterating over all players

Spigot-Server-Patches/Optimise-IEntityAccess-getPlayerByUUID.patch

@@ -0,0 +1,45 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Spottedleaf <Spottedleaf@users.noreply.github.com>
+Date: Sat, 11 Jan 2020 21:50:56 -0800
+Subject: [PATCH] Optimise IEntityAccess#getPlayerByUUID
+
+Use the world entity map instead of iterating over all players
+
+diff --git a/src/main/java/net/minecraft/server/IEntityAccess.java b/src/main/java/net/minecraft/server/IEntityAccess.java
+index c8512f9f4..467b35e3c 100644
+--- a/src/main/java/net/minecraft/server/IEntityAccess.java
++++ b/src/main/java/net/minecraft/server/IEntityAccess.java
+@@ -0,0 +0,0 @@ public interface IEntityAccess {
+ 
+     @Nullable
+     default EntityHuman b(UUID uuid) {
++        // Paper start - allow WorldServer to override
++        return this.getPlayerByUUID(uuid);
++    }
++    @Nullable
++    default EntityHuman getPlayerByUUID(UUID uuid) {
++        // Paper end
+         for (int i = 0; i < this.getPlayers().size(); ++i) {
+             EntityHuman entityhuman = (EntityHuman) this.getPlayers().get(i);
+ 
+diff --git a/src/main/java/net/minecraft/server/WorldServer.java b/src/main/java/net/minecraft/server/WorldServer.java
+index 70cbff313..8526a3fda 100644
+--- a/src/main/java/net/minecraft/server/WorldServer.java
++++ b/src/main/java/net/minecraft/server/WorldServer.java
+@@ -0,0 +0,0 @@ public class WorldServer extends World {
+         return new Throwable(entity + " Added to world at " + new java.util.Date());
+     }
+ 
++    // Paper start - optimise getPlayerByUUID
++    @Nullable
++    @Override
++    public EntityHuman getPlayerByUUID(UUID uuid) {
++        Entity player = this.entitiesByUUID.get(uuid);
++        return (player instanceof EntityHuman) ? (EntityHuman)player : null;
++    }
++    // Paper end
++
+     // Paper start - Asynchronous IO
+     public final com.destroystokyo.paper.io.PaperFileIOThread.ChunkDataController poiDataController = new com.destroystokyo.paper.io.PaperFileIOThread.ChunkDataController() {
+         @Override
+--