Imported Upstream version 5.14.0.78

Former-commit-id: 3494343bcc9ddb42b36b82dd9ae7b69e85e0229f

mcs/class/corlib/corert/RuntimeThread.cs

@@ -1,14 +1,37 @@
+using System;
+using System.Threading;
+
 namespace Internal.Runtime.Augments
 {
 	class RuntimeThread
 	{
-		public static RuntimeThread InitializeThreadPoolThread ()
+		readonly Thread thread;
+
+		RuntimeThread (Thread t) { thread = t; }
+		
+		public void ResetThreadPoolThread () {}
+		
+		public static RuntimeThread InitializeThreadPoolThread () => default;
+
+		public static RuntimeThread Create (ParameterizedThreadStart start, int maxStackSize) 
+			=> new RuntimeThread (new Thread (start, maxStackSize));
+
+		public bool IsBackground
 		{
-			return default;
+			get => thread.IsBackground;
+			set => thread.IsBackground = value;
 		}
 
-		public void ResetThreadPoolThread ()
+		public void Start () => thread.Start ();
+
+		public void Start (object state) => thread.Start (state);
+
+		public static bool Yield () => Thread.Yield ();
+
+		public static bool SpinWait (int iterations)
 		{
+			Thread.SpinWait (iterations);
+			return true;
 		}
 	}
 }