SpinLock VB.Net Example From MSDN Possibly Produces Incorrect Behaviour

The code below is part of an example from MSDN. It is the example on how to use SpinLock but to my eye there is a race condition in it. Why I think this is because of the Dim lockTaken As Boolean = False line in the UpdateWithSpinLock method. It appears to me that the following could occur: Thread 1 enters UpdateWithSpinLock method and executes as far as _queue.Enqueue(d) and a context switch occurs. Thread 1 now has the SpinLock and lockTaken is True. Thread 2 enters and only executes as far as the line Dim lockTaken As Boolean = False. Thread 2 has now set lockTaken back to False and a context switch occurs. Thread 1 continues and tests lockTaken in the Finally block and finds it to be False (it should be True for Thread 1) so doesn't release the SpinLock. Thread 1 exits the method leaving the lock inplace and thread 2 waiting forever. Imports System.Threading Imports System.Threading.Tasks Class SpinLockDemo2 Const N As Integer = 100000 Shared _queue = New Queue(Of Data)() Shared _lock = New Object() Shared _spinlock = New SpinLock() Class Data Public Name As String Public Number As Double End Class Shared Sub Main() UseSpinLock() Console.WriteLine("Press a key") Console.ReadKey() End Sub Private Shared Sub UpdateWithSpinLock(ByVal d As Data, ByVal i As Integer) Dim lockTaken As Boolean = False Try _spinlock.Enter(lockTaken) _queue.Enqueue(d) Finally If lockTaken Then _spinlock.Exit(False) End If End Try End Sub Private Shared Sub UseSpinLock() Dim sw = Stopwatch.StartNew() Parallel.Invoke( Sub() For i As Integer = 0 To N - 1 UpdateWithSpinLock(New Data() With {.Name = i.ToString(), .Number = i}, i) Next End Sub, Sub() For i As Integer = 0 To N - 1 UpdateWithSpinLock(New Data() With {.Name = i.ToString(), .Number = i}, i) Next End Sub ) sw.Stop() Console.WriteLine("elapsed ms with spinlock: {0}", sw.ElapsedMilliseconds) End Sub Shared Sub UpdateWithLock(ByVal d As Data, ByVal i As Integer) SyncLock (_lock) _queue.Enqueue(d) End SyncLock End Sub Private Shared Sub UseLock() Dim sw = Stopwatch.StartNew() Parallel.Invoke( Sub() For i As Integer = 0 To N - 1 UpdateWithLock(New Data() With {.Name = i.ToString(), .Number = i}, i) Next End Sub, Sub() For i As Integer = 0 To N - 1 UpdateWithLock(New Data() With {.Name = i.ToString(), .Number = i}, i) Next End Sub ) sw.Stop() Console.WriteLine("elapsed ms with lock: {0}", sw.ElapsedMilliseconds) End Sub End Class Is the way I'm interpreting this correct. If it's not could you please show me what I'm missing. Thanks in advance.