Fix Observer not using new generic Iterator

src/gaemstone.ECS/Observer.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Runtime.InteropServices;
-using gaemstone.ECS.Internal;
 using gaemstone.ECS.Utility;
 using static flecs_hub.flecs;
 
@@ -15,11 +14,12 @@ public static class ObserverExtensions
 		if (events.Length >  8) throw new ArgumentException("Must specify at most 8 events", nameof(events));
 
 		var world = entity.World;
+		var internalCallback = (nint iterPtr) => callback(new((ecs_iter_t*)iterPtr));
 		using var alloc = TempAllocator.Use();
 		var desc = new ecs_observer_desc_t {
 			entity = entity,
 			filter = filter.ToFlecs(alloc),
-			binding_ctx      = (void*)CallbackContextHelper.Create((world, callback)),
+			binding_ctx      = (void*)CallbackContextHelper.Create(internalCallback),
 			binding_ctx_free = new() { Data = new() { Pointer = &FreeContext } },
 			callback         = new() { Data = new() { Pointer = &Callback } },
 		};
@@ -33,11 +33,9 @@ public static class ObserverExtensions
 
 	[UnmanagedCallersOnly]
 	private static unsafe void Callback(ecs_iter_t* iter)
-	{
-		var (world, callback) = CallbackContextHelper
-			.Get<(World, Action<Iterator>)>((nint)iter->binding_ctx);
-		callback(new Iterator(iter));
-	}
+		=> CallbackContextHelper
+			.Get<Action<nint>>((nint)iter->binding_ctx)
+			.Invoke((nint)iter);
 
 	[UnmanagedCallersOnly]
 	private static unsafe void FreeContext(void* context)

src/gaemstone.ECS/System.cs

@@ -12,7 +12,7 @@ public static class SystemExtensions
 	{
 		var world = entity.World;
 		var internalCallback = (nint iter) =>
-			callback(new Iterator<TContext>((ecs_iter_t*)iter));
+			callback(new((ecs_iter_t*)iter));
 		using var alloc = TempAllocator.Use();
 		var desc = new ecs_system_desc_t {
 			entity = entity,