[Physics] Prevent invalid state when component was added right after …

…removal (stride3d#799)

* [Physics] Prevent invalid state when component was added right after removal

* Use a HashSet for faster search/remove

sources/engine/Stride.Physics/Engine/PhysicsProcessor.cs

@@ -103,6 +103,10 @@ protected override bool IsAssociatedDataValid(Entity entity, PhysicsComponent ph
 
         protected override void OnEntityComponentAdding(Entity entity, PhysicsComponent component, AssociatedData data)
         {
+            // Tagged for removal? If yes, cancel it
+            if (currentFrameRemovals.Remove(component))
+                return;
+
             component.Attach(data);
 
             var character = component as CharacterComponent;
@@ -149,7 +153,7 @@ private void ComponentRemoval(PhysicsComponent component)
             component.Detach();
         }
 
-        private readonly List<PhysicsComponent> currentFrameRemovals = new List<PhysicsComponent>();
+        private readonly HashSet<PhysicsComponent> currentFrameRemovals = new HashSet<PhysicsComponent>();
 
         protected override void OnEntityComponentRemoved(Entity entity, PhysicsComponent component, AssociatedData data)
         {