anchor.diff:          member x.Remove(n : LodDataNode) =
               match geometries.TryRemove n with
                   | (true,v) ->
  -                    Interlocked.Decrement(&desiredCount) |> ignore
  +                    Interlocked.Decrement(progress.ExpectedNodeCount) |> ignore
                       match Interlocked.Exchange(v,Unchecked.defaultof<_>) with
                           | Choice1Of2 ct -> 
                               Log.line "cancelling import."
  
positive.code: 
              if calls.Add n.range then
                  Interlocked.Add(&activeSize, int64 size) |> ignore
                  Interlocked.Increment(&activeCount) |> ignore
  
  
          let deactivate (n : GeometryRef) =
  
negative.code:                                 | _ ->
                                      Log.warn "inactive: %A / count : %A" inactiveSize inactive.Count 
                                      inactiveSize <- 0L
                              
                          do! Async.Sleep node.Config.pruneInterval
                  }
  