Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

external/referencesource/mscorlib/system/threadattributes.cs

@@ -0,0 +1,40 @@
+// ==++==
+// 
+//   Copyright (c) Microsoft Corporation.  All rights reserved.
+// 
+// ==--==
+/*=============================================================================
+**
+** File: ThreadAttributes.cs
+**
+** Author: 
+**
+** Purpose: For Threads-related custom attributes.
+**
+** Date: July, 2000
+**
+=============================================================================*/
+
+
+namespace System {
+    [AttributeUsage (AttributeTargets.Method)]  
+[System.Runtime.InteropServices.ComVisible(true)]
+#if FEATURE_CORECLR && !FEATURE_NETCORE
+    [Obsolete("STAThreadAttribute is not supported in this release. It has been left in so that legacy tools can be used with this release, but it cannot be used in your code.", true)] 
+#endif // FEATURE_CORECLR
+    public sealed class STAThreadAttribute : Attribute
+    {
+        public STAThreadAttribute()
+        {
+        }
+    }
+
+    [AttributeUsage (AttributeTargets.Method)]  
+[System.Runtime.InteropServices.ComVisible(true)]
+    public sealed class MTAThreadAttribute : Attribute
+    {
+        public MTAThreadAttribute()
+        {
+        }
+    }
+}