anchor.diff:            this.values <- vArr
             OptimizationSettings.ArrayPool.ReturnBuffer(toReturn)
           | _ -> ()
  -      finally
  +      //finally
           exitLockIf syncRoot entered
   
     member this.Comparer with get() = comparer
  
positive.code:         0
        else
          let entered = enterLockIf this.SyncRoot this.IsSynchronized
          try
            match option with
            | AppendOption.ThrowOnOverlap _ ->
              if this.IsEmpty || comparer.Compare(appendMap.First.Key, this.Last.Key) > 0 then
  
negative.code:     this.IndexOfKeyUnchecked(key)
  
    member this.IndexOfValue(value:'V) : int =
        let entered = enterLockIf syncRoot  isSynchronized
      //try
        let mutable res = 0
        let mutable found = false
        let valueComparer = Comparer<'V>.Default;
  