Managed Synchronization Primitives and Thread Apartment States

The managed synchronization mechanisms, including Monitor, WaitHandle.WaitAny, ManualResetEvent, ReaderWriterLock, Thread.Join, GC.WaitForPendingFinalizers and the rest of the family are not just a thin platform adaptation layer on top of the Win32 API. The CLR needs to know exactly which threads are currently waiting for a synchronization mechanisms for a variety of reasons. To mention two of them: