Entity removal should be on the main thread as we're just passing through rather than doing chunk operations

- Fixes #1164
 - Not working: butcher/remove history

worldedit-core/src/main/java/com/sk89q/worldedit/command/UtilityCommands.java

@@ -25,6 +25,7 @@ import com.fastasyncworldedit.core.configuration.Settings;
 import com.fastasyncworldedit.core.object.DelegateConsumer;
 import com.fastasyncworldedit.core.object.function.QuadFunction;
 import com.fastasyncworldedit.core.util.MainUtil;
+import com.fastasyncworldedit.core.util.TaskManager;
 import com.fastasyncworldedit.core.util.image.ImageUtil;
 import com.google.common.base.Function;
 import com.sk89q.worldedit.EditSession;
@@ -636,7 +637,8 @@ public class UtilityCommands {
         flags.or(CreatureButcher.Flags.ARMOR_STAND, killArmorStands, "worldedit.butcher.armorstands");
         flags.or(CreatureButcher.Flags.WATER, killWater, "worldedit.butcher.water");
 
-        int killed = killMatchingEntities(radius, actor, flags::createFunction);
+        int finalRadius = radius;
+        int killed = TaskManager.IMP.sync(() -> killMatchingEntities(finalRadius, actor, flags::createFunction));
 
         actor.print(Caption.of(
                 "worldedit.butcher.killed",
@@ -664,7 +666,7 @@ public class UtilityCommands {
             return 0;
         }
 
-        int removed = killMatchingEntities(radius, actor, remover::createFunction);
+        int removed =  TaskManager.IMP.sync(() -> killMatchingEntities(radius, actor, remover::createFunction));
         actor.print(Caption.of("worldedit.remove.removed", TextComponent.of(removed)));
         return removed;
     }