anchor.diff:                  if not propertyContent.PropertyInitializer || initializing then
                       let lens = propertyContent.PropertyLens
                       match lens.Name with
  -                    | "Size" -> sizeFound <- true
                       | "MountOpt" -> mountOptFound <- true
                       | _ -> ()
                       let entity = match lens.This :> obj with null -> entity | _ -> lens.This :?> Entity
  
positive.code:     ///
      let rec synchronizeEntity initializing relating (contentOld : EntityContent) (content : EntityContent) (origin : Simulant) (entity : Entity) world =
          if contentOld <> content then
              let mutable sizeFound = false
              let mutable mountOptFound = false
              let world = synchronizeEventSignals contentOld content origin entity world
              let world = synchronizeEventHandlers contentOld content origin entity world
              let world = synchronizeEntityPropertiesFast (initializing, contentOld, content, entity, world, &sizeFound, &mountOptFound)
              let world =
                  if initializing then
                      let world =
                          if not sizeFound
                          then World.setEntitySize (World.getEntityQuickSize entity world) entity world |> snd'
                          else world
                      let world =
                          if not mountOptFound && relating
                          then World.setEntityMountOpt (Some (Relation.makeParent ())) entity world |> snd'
                          else world
                      world
                  else world
              match tryDifferentiateChildren<Entity, EntityContent> contentOld content entity with
              | Some (entitiesAdded, entitiesRemoved, entitiesPotentiallyAltered) ->
  
negative.code: #if !DEBUG
          inline
  #endif
          private synchronizeEntityPropertiesFast (initializing, contentOld : EntityContent, content : EntityContent, entity : Entity, world, mountOptFound : bool outref) =
          if notNull content.PropertyContentsOpt && content.PropertyContentsOpt.Count > 0 then
              let entity = if notNull (contentOld.EntityCachedOpt :> obj) then contentOld.EntityCachedOpt else entity
              content.EntityCachedOpt <- entity
  