So it begins...

patches/unapplied/server/Inline-shift-direction-fields.patch

@@ -0,0 +1,55 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Andrew Steinborn <git@steinborn.me>
+Date: Mon, 18 Jan 2021 20:45:25 -0500
+Subject: [PATCH] Inline shift direction fields
+
+Removes a layer of indirection for EnumDirection.getAdjacent(X|Y|Z)(), which is in the
+critical section for much of the server, including the lighting engine.
+
+diff --git a/src/main/java/net/minecraft/core/Direction.java b/src/main/java/net/minecraft/core/Direction.java
+index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
+--- a/src/main/java/net/minecraft/core/Direction.java
++++ b/src/main/java/net/minecraft/core/Direction.java
+@@ -0,0 +0,0 @@ public enum Direction implements StringRepresentable {
+     })).toArray((i) -> {
+         return new Direction[i];
+     });
++    // Paper start
++    private final int adjX;
++    private final int adjY;
++    private final int adjZ;
++    // Paper end
+ 
+     private Direction(int id, int idOpposite, int idHorizontal, String name, Direction.AxisDirection direction, Direction.Axis axis, Vec3i vector) {
+         this.data3d = id;
+@@ -0,0 +0,0 @@ public enum Direction implements StringRepresentable {
+         this.axis = axis;
+         this.axisDirection = direction;
+         this.normal = vector;
++        // Paper start
++        this.adjX = vector.getX();
++        this.adjY = vector.getY();
++        this.adjZ = vector.getZ();
++        // Paper end
+     }
+ 
+     public static Direction[] orderedByNearest(Entity entity) {
+@@ -0,0 +0,0 @@ public enum Direction implements StringRepresentable {
+     }
+ 
+     public int getStepX() {
+-        return this.normal.getX();
++        return this.adjX; // Paper
+     }
+ 
+     public int getStepY() {
+-        return this.normal.getY();
++        return this.adjY; // Paper
+     }
+ 
+     public int getStepZ() {
+-        return this.normal.getZ();
++        return this.adjZ; // Paper
+     }
+ 
+     public Vector3f step() {