Rework async chunk api implementation

Firstly, the old methods all routed to the CompletableFuture method.
However, the CF method could not guarantee that if the caller
was off-main that the future would be "completed" on-main. Since
the callback methods used the CF one, this meant that the callback
methods did not guarantee that the callbacks were to be called on
the main thread.

Now, all methods route to getChunkAtAsync(x, z, gen, urgent, cb)
so that the methods with the callback are guaranteed to invoke
the callback on the main thread. The CF behavior remains unchanged;
it may still appear to complete on main if invoked off-main.

Secondly, remove the scheduleOnMain invocation in the async
chunk completion. This unnecessarily delays the callback
by 1 tick.

Thirdly, add getChunksAtAsync(minX, minZ, maxX, maxZ, ...) which
will load chunks within an area. This method is provided as a helper
as keeping all chunks loaded within an area can be complicated to
implement for plugins (due to the lacking ticket API), and is
already implemented internally anyways.

Fourthly, remove the ticket addition that occured with getChunkAt
and getChunkAtAsync. The ticket addition may delay the unloading
of the chunk unnecessarily. It also fixes a very rare timing bug
where the future/callback would be completed after the chunk
unloads.

patches/server/0701-Prevent-entity-loading-causing-async-lookups.patch

@@ -1,81 +0,0 @@
-From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
-From: Owen1212055 <23108066+Owen1212055@users.noreply.github.com>
-Date: Sun, 6 Mar 2022 11:09:09 -0500
-Subject: [PATCH] Prevent entity loading causing async lookups
-
-
-diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
-index 612abe47627f0e7c69aa8bfaeee1de4fda528a57..828535741f9e39693fe9055ae1f5af2258668ae3 100644
---- a/src/main/java/net/minecraft/world/entity/Entity.java
-+++ b/src/main/java/net/minecraft/world/entity/Entity.java
-@@ -725,6 +725,7 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
-         ProfilerFiller gameprofilerfiller = Profiler.get();
- 
-         gameprofilerfiller.push("entityBaseTick");
-+        if (firstTick && this instanceof net.minecraft.world.entity.NeutralMob neutralMob) neutralMob.tickInitialPersistentAnger(level); // Paper - Prevent entity loading causing async lookups
-         this.inBlockState = null;
-         if (this.isPassenger() && this.getVehicle().isRemoved()) {
-             this.stopRiding();
-diff --git a/src/main/java/net/minecraft/world/entity/NeutralMob.java b/src/main/java/net/minecraft/world/entity/NeutralMob.java
-index bf577b06707ff197f13f0b5e16620c09d4a69fa8..053d947c4cc00096dae422df36fb8351b3266215 100644
---- a/src/main/java/net/minecraft/world/entity/NeutralMob.java
-+++ b/src/main/java/net/minecraft/world/entity/NeutralMob.java
-@@ -45,24 +45,11 @@ public interface NeutralMob {
-                 UUID uuid = nbt.getUUID("AngryAt");
- 
-                 this.setPersistentAngerTarget(uuid);
--                Entity entity = ((ServerLevel) world).getEntity(uuid);
--
--                if (entity != null) {
--                    if (entity instanceof Mob) {
--                        Mob entityinsentient = (Mob) entity;
--
--                        this.setTarget(entityinsentient, EntityTargetEvent.TargetReason.UNKNOWN, false); // CraftBukkit
--                        this.setLastHurtByMob(entityinsentient);
--                    }
--
--                    if (entity instanceof Player) {
--                        Player entityhuman = (Player) entity;
--
--                        this.setTarget(entityhuman, EntityTargetEvent.TargetReason.UNKNOWN, false); // CraftBukkit
--                        this.setLastHurtByPlayer(entityhuman);
--                    }
--
--                }
-+                // Paper - Prevent entity loading causing async lookups; Moved diff to separate method
-+                // If this entity already survived its first tick, e.g. is loaded and ticked in sync, actively
-+                // tick the initial persistent anger.
-+                // If not, let the first tick on the baseTick call the method later down the line.
-+                if (this instanceof Entity entity && !entity.firstTick) this.tickInitialPersistentAnger(world);
-             }
-         }
-     }
-@@ -136,4 +123,28 @@ public interface NeutralMob {
- 
-     @Nullable
-     LivingEntity getTarget();
-+
-+    // Paper start - Prevent entity loading causing async lookups
-+    // Update last hurt when ticking
-+    default void tickInitialPersistentAnger(Level level) {
-+        UUID target = getPersistentAngerTarget();
-+        if (target == null) {
-+            return;
-+        }
-+
-+        Entity entity = ((ServerLevel) level).getEntity(target);
-+
-+        if (entity != null) {
-+            if (entity instanceof Mob mob) {
-+                this.setTarget(mob, EntityTargetEvent.TargetReason.UNKNOWN, false); // CraftBukkit
-+                this.setLastHurtByMob(mob);
-+            }
-+
-+            if (entity instanceof Player player) {
-+                this.setTarget(player, EntityTargetEvent.TargetReason.UNKNOWN, false); // CraftBukkit
-+                this.setLastHurtByPlayer(player);
-+            }
-+        }
-+    }
-+    // Paper end - Prevent entity loading causing async lookups
- }