Async Operation Catching

Catch and throw an exception when a potentially unsafe operation occurs on a thread other than the main server thread.

By: md_5 <git@md-5.net>

paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java

@@ -228,6 +228,7 @@ public abstract class CraftEntity implements org.bukkit.entity.Entity {
     @Override
     public List<org.bukkit.entity.Entity> getNearbyEntities(double x, double y, double z) {
         Preconditions.checkState(!this.entity.generation, "Cannot get nearby entities during world generation");
+        org.spigotmc.AsyncCatcher.catchOp("getNearbyEntities"); // Spigot
 
         List<Entity> notchEntityList = this.entity.level().getEntities(this.entity, this.entity.getBoundingBox().inflate(x, y, z), Predicates.alwaysTrue());
         List<org.bukkit.entity.Entity> bukkitEntityList = new java.util.ArrayList<org.bukkit.entity.Entity>(notchEntityList.size());

paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java

@@ -492,6 +492,7 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
 
     @Override
     public void kickPlayer(String message) {
+        org.spigotmc.AsyncCatcher.catchOp("player kick"); // Spigot
         this.getHandle().transferCookieConnection.kickPlayer(CraftChatMessage.fromStringOrEmpty(message, true));
     }