Add Iterator<>.First()

src/gaemstone.ECS/Iterator.cs

@@ -29,6 +29,8 @@ public unsafe class Iterator<TContext> : Iterator
 	public new Iterator<TContext> SetVar(Variable var, Entity entity)
 		=> (Iterator<TContext>)base.SetVar(var, entity);
 
+	public new Entity<TContext>? First()
+		=> Entity<TContext>.GetOrNull(World, base.First());
 	public new IEnumerable<Entity<TContext>> GetAllEntities()
 		=> base.GetAllEntities().Select(e => Entity<TContext>.GetOrInvalid(World, e));