anchor.diff:      member this.NextEntityId world =
           let world =
               if unallocated.Count = 0
  -            then this.Preallocate Constants.Ecs.PreallocateAmount world
  +            then this.Expand Constants.Ecs.PreallocateAmount world
               else world
           let entityIdInv = Seq.head unallocated
           let entityId = UInt64.MaxValue - entityIdInv
  
positive.code:             world <- this.RegisterCorrelated true Unchecked.defaultof<'c> Unchecked.defaultof<'c2> Unchecked.defaultof<'c3> Unchecked.defaultof<'c4> Unchecked.defaultof<'c5> Unchecked.defaultof<'c6> Unchecked.defaultof<'c7> entityId world
          world
  
      member this.Clear world =
          let mutable world = world
          for entityId in Seq.append allocated (Seq.map (fun inv -> UInt64.MaxValue - inv) unallocated) do
              world <- this.UnregisterCorrelated entityId world |> snd'
          unallocated.Clear ()
          world
  
negative.code:     member this.System2 = system2
      member this.System3 = system3
      member this.System4 = system4
      member this.Cached = cache.Keys
      member this.Allocated = allocated.AsReadOnly ()
  
      member this.Contains entityId =
          cache.ContainsKey entityId
  