Description / Repro Steps:
UnityVS debugger is causing threads that are suspended via calls to System.Threading.Monitor.Wait() to be woken back up again. This in turn wreaks havoc on low level synchronization primitives such as ManualResetEventSlim.

Version 5.4.0b7 (435d6f5b598c)
Windows 10 | OS x64 | 16 GB RAM | Intel Proc i7

Repro Steps:
1. Open a new Unity Project
2. Create a new GameObject
3. Attach the script provided
4. Observe - If you hit play without a debugger attached, it works as expected and the Monitor.Wait call blocks the thread for 2 seconds and then returns true.
5. Observe - If I hit play with a UnityVS debugger attached, the Wait() operation immediately returns false.

Expected:
Attaching a debugger doesn’t cause suspended threads to awake

Actual:
Suspended threads are being woken back up with a UnityVS debugger attached