GameHost wanted HelloWorld!.cs

namespace PataponGameHost.Systems
{
    public struct Character
    {
    }

    [RestrictToApplication(typeof(GameSimulationThreadingHost))]
    public class MoveCharacterSystem : AppSystem
    {
        // Injected field
        private readonly IManagedWorldTime worldTime;

        public MoveCharacterSystem(IManagedWorldTime worldTime) 
        {
            this.worldTime = worldTime;
        }

        private EntitySet     characterSet;
        private Inputs.Axis2D moveAction;

        protected override void OnInit()
        {
            base.OnInit();

            moveAction   = World.GetOrCreate<InputManager>().GetAction<MyInputMap, Inputs.Axis2D>("move");
            characterSet = World.Mgr.GetEntities()
                                .With<Character>()
                                .With<Vector3>()
                                .AsSet();
            
            for (var i = 0; i != 1_000_000; i++)
            {
                var ch = World.Mgr.CreateEntity();
                ch.Set(new Character());
                ch.Set(new Vector3());
            }
        }

        protected override void OnUpdate()
        {
            base.OnUpdate();

            var moveVector = moveAction.Value;
            var dt         = worldTime.Delta;
            
            moveVector = Vector2.NormalizeSafe(moveVector) * dt;
            foreach (int batch in characterSet.ToParallelBatch(batchCountTarget: 1 / 4))
            {
                foreach (ref readonly var entity in batch)
                {
                    entity.Get<Vector3>() += moveVector;
                }
            }
        }
    }
}