Imported Upstream version 6.4.0.137

Former-commit-id: 943baa9f16a098c33e129777827f3a9d20da00d6

mcs/class/corlib/corefx/DiagnosticCounter.cs

@@ -0,0 +1,18 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace System.Diagnostics.Tracing
+{
+    public abstract partial class DiagnosticCounter : IDisposable
+    {
+        internal DiagnosticCounter (string name, EventSource eventSource) { }
+        internal DiagnosticCounter () { }
+        public string DisplayName { get; set; }
+        public string DisplayUnits { get; set; }
+        public EventSource EventSource { get; }
+        public string Name { get; }
+        public void AddMetadata (string key, string value) { }
+        public void Dispose () { }
+    }
+}