anchor.diff:              res :> IDisposable //{ new IDisposable with member __.Dispose() = live := false; x.MarkingCallbacks.Remove !self |> ignore}
    
   
  -
  -open System.Threading
  - 
  +  
   /// <summary>
   /// defines a base class for all decorated mods
   /// </summary>
  
positive.code: open System.Collections.Concurrent
  open System.Threading
  open System.Linq
  
  [<AllowNullLiteral>]
  type IWeakable<'a when 'a : not struct> =
  
negative.code:     /// to be represented by Weak references in order to allow for
      /// unused parts of the graph to be garbage collected.
      /// </summary>
      abstract member Outputs : VolatileCollection
  
  
      abstract member InputChanged : obj * IAdaptiveObject -> unit
  