anchor.diff:              elif cursorVersion =  this.orderVersion then
                 if index > 0 && index < this.size then
                   index <- previousIndex
  -                currentKey <- this.GetKeyByIndex(index)
  +                currentKey <- this.GetKeyByIndexUnchecked(index)
                   currentValue <- this.values.[index]
                   true
                 else
  
positive.code: 
    /// Removes all elements that are to `direction` from `key`
    member this.RemoveMany(key:'K,direction:Lookup) : bool =
      let entered = enterWriteLockIf &locker this.isSynchronized
      if entered then incrementVolatile64 &this.nextOrderVersion
      try
  
negative.code:     // NB: There is no single imaginable reason not to have it true by default!
      // Uncontended performance is close to non-synced.
      this.isSynchronized <- true
  
      let tempCap = if capacity.IsSome && capacity.Value > 0 then capacity.Value else 2
      if dictionary.IsNone || dictionary.Value.Count = 0 then // otherwise we will set them in dict processing part
  