Return non-fastutil type

src/main/java/net/minestom/server/MinecraftServer.java

@@ -486,7 +486,7 @@ public final class MinecraftServer {
 
                     player.refreshVisibleChunks(playerChunk);
                 }
-            });
+            }
         }
     }
 

src/main/java/net/minestom/server/instance/Chunk.java

@@ -197,7 +197,7 @@ public abstract class Chunk implements Viewable, DataContainer {
      * @return the block entities in this chunk
      */
     @NotNull
-    public abstract IntSet getBlockEntities();
+    public abstract Set<Integer> getBlockEntities();
 
     /**
      * Gets the last time that this chunk changed.

src/main/java/net/minestom/server/instance/DynamicChunk.java

@@ -193,7 +193,7 @@ public class DynamicChunk extends Chunk {
 
     @NotNull
     @Override
-    public IntSet getBlockEntities() {
+    public Set<Integer> getBlockEntities() {
         return blockEntities;
     }