anchor.diff:        let mutable doSwitchInner = false
         let mutable result = Unchecked.defaultof<_>
         let mutable doSpin = true
  +      let mutable outerMoved = false
         let sw = new SpinWait()
         while doSpin do
           doSpin <- this.source.isSynchronized
  
positive.code:                   doSwitchInner <- true
                    true
                  else
                    if this.outerCursor.MoveNext() then
                      this.isBatch <- false // if was batch, moved to the first element of the new batch
                      newInner <- new SortedMapCursor<'K,'V>(this.outerCursor.CurrentValue)
                      doSwitchInner <- true
                      newInner.MoveNext()
                    else false
                finally
                  exitWriteLockIf &this.source.locker entered
            with
  
negative.code:       let mutable doSwitchInner = false
        let mutable result = Unchecked.defaultof<_>
        let mutable doSpin = true
        let mutable outerMoved = false
        let sw = new SpinWait()
        while doSpin do
          doSpin <- this.source.isSynchronized
  