use clearly named method

encompass-cs/Engine.cs

@@ -486,7 +486,7 @@ namespace Encompass
         /// </exception>
         protected void AddComponent<TComponent>(Entity entity, TComponent component) where TComponent : struct, IComponent
         {
-            if (!_newlyCreatedEntities.Contains(entity.ID))
+            if (!EntityCreatedThisFrame(entity.ID))
             {
                 throw new IllegalWriteException("AddComponent used on Entity that was not created in this context. Use SetComponent instead.");
             }