SynchronizationContext bug.cs

using System;
using System.Threading;

namespace Foo
{
	public class Pr
	{
		public static void Main(string[] args)
		{
			var tsc = new TestSynchronizationContext();
			SynchronizationContext.SetSynchronizationContext(tsc);
			var e = new ManualResetEvent(false);
			tsc.WaitAction = () => e.Set();
			tsc.SetWaitNotificationRequired();
			Console.WriteLine("WaitOne: " + e.WaitOne(0));
			//.NET Core & .NET: true
			//Mono: false
		}
	}

	class TestSynchronizationContext : SynchronizationContext
	{
		public Action WaitAction { get; set; }

		public new void SetWaitNotificationRequired()
		{
			base.SetWaitNotificationRequired();
		}

		public override int Wait(IntPtr[] waitHandles, bool waitAll, int millisecondsTimeout)
		{
			// Mono doesn't trigger this method
			WaitAction?.Invoke();
			return base.Wait(waitHandles, waitAll, millisecondsTimeout);
		}
	}
}