anchor.diff:  
   type private ResourceContainer<'Resource>(name : string, proj : 'Resource -> string) =
       let container = new ConcurrentDictionary<string, 'Resource> ()
  +
  +    member __.ContainsKey(id : string) = container.ContainsKey id
  +
  +    member __.TryRegister(resource : 'Resource, ?force : bool) =
  +        let key = proj resource
  +        if defaultArg force false then
  +            container.AddOrUpdate(key, resource, fun _ _ -> resource) |> ignore
  +            true
  +        else 
  +            container.TryAdd(key, resource)
   
       member __.Register(resource : 'Resource, ?force : bool) =
           let key = proj resource
  
positive.code:     static member Register(tableStore : ICloudTableStore, ?force : bool) : unit = tableStores.Register(tableStore, ?force = force)
  
      /// <summary>
      ///     Resolves a registered serializer instance by id.
      /// </summary>
      /// <param name="id">Serializer id.</param>
  
negative.code:     ///     Resolves a registered TableStore instance by id.
      /// </summary>
      /// <param name="id">Table store id.</param>
      static member GetTableStore(id : string) = tableStores.Resolve(id)
  
      /// <summary>
      ///     Checks if serializer with given id is registered.
      /// </summary>
      /// <param name="serializer">Serializer id</param>
      member __.ContainsSerializer(serializerId : string) = serializers.ContainsKey serializerId
  
      /// <summary>
      ///     Checks if file store with given id is registered.
      /// </summary>
      /// <param name="fileStoreId">FileStore id.</param>
      member __.ContainsFileStore(fileStoreId : string) = fileStores.ContainsKey fileStoreId
  
      /// <summary>
      ///     Checks if table store with given id is registered.
      /// </summary>
      /// <param name="tableStoreId">TableStore id.</param>
      member __.ContainsTableStore(tableStoreId : string) = tableStores.ContainsKey tableStoreId