Worker thread IDs: 3, 4
>> STARTING: Worker 0 on 3
>> STARTING: Worker 1 on 4
>> STARTING: Worker 2 on 4
>> STARTING: Worker 3 on 3
>> STARTING: Worker 4 on 4
>> STARTING: Worker 6 on 4
>> STARTING: Worker 7 on 4
>> STARTING: Worker 5 on 3
>> STARTING: Worker 9 on 3
>> STARTING: Worker 8 on 4

Unhandled Exception:
System.NullReferenceException: Object reference not set to an instance of an object
  at System.Threading.Microsoft.ThreadPoolWorkQueue.Enqueue (IThreadPoolWorkItem callback, Boolean forceGlobal) <0x18fff00 + 0x00112> in <filename unknown>:0
  at System.Threading.Microsoft.ThreadPool.QueueUserWorkItemHelper (System.Threading.WaitCallback callBack, System.Object state, System.Threading.StackCrawlMark& stackMark, Boolean compressStack) <0x18ff950 + 0x000cb> in <filename unknown>:0
  at System.Threading.Microsoft.ThreadPool.QueueUserWorkItem (System.Threading.WaitCallback callBack, System.Object state) <0x18ff908 + 0x00037> in <filename unknown>:0
  at System.Threading.ThreadPool.QueueWorkItem (System.Threading.WaitCallback callBack, System.Object state) <0x18ff8e0 + 0x00017> in <filename unknown>:0
  at System.Threading.Timer+Scheduler.SchedulerThread () <0x18fa0c0 + 0x002d3> in <filename unknown>:0
  at System.Threading.Thread.StartInternal () <0x17ec598 + 0x00054> in <filename unknown>:0