anchor.diff:              Stream.insert Gen.id |>
               Stream.mapWorld (fun (guid, lenses) world ->
                   lenses |>
  -                Seq.map (fun lens -> (lens.Get world, Lens.dereference lens)) |>
  +                Seq.map (fun lens -> (lens.Get world, World.dereferenceLensHack lens)) |>
                   Seq.filter (fst >> Option.isSome) |>
                   Seq.take (Lens.get lensSeq world |> Seq.length) |>
                   Seq.map (fun (opt, lens) ->
  
positive.code: [<AutoOpen>]
  module WorldDeclarative =
  
      type World with
  
          /// Transform a stream into existing simulants.
          static member streamSimulants
  
negative.code:                         match World.tryGetKeyedValue (scstring guid) world with
                          | Some simulant ->
                              let world = World.removeKeyedValue (scstring guid) world
                              WorldModule.destroy simulant world
                          | None -> failwithumf ())
                          world removed
  