Entitas manual ID system

EntityHelper.cs

using Entitas.CodeGeneration.Attributes;

public static class EntityHelper {
  public static T CreateEntityWithId<T>(this Context<T> @this) where T : class, IIdEntity, IEntity {
    var entity = @this.CreateEntity();
    entity.AddId(entity.creationIndex);
    return entity;
  }
}

[Engine, Debug, Draw, InputDevice]
public sealed class IdComponent : Entitas.IComponent {
  [PrimaryEntityIndex] public int Value;
}