Imported Upstream version 4.3.2.467

Former-commit-id: 9c2cb47f45fa221e661ab616387c9cda183f283d

mcs/class/System.Threading.Tasks.Dataflow/CoreFxSources/Internal/IDebuggerDisplay.cs

@@ -0,0 +1,27 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+// =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
+//
+// IDebuggerDisplay.cs
+//
+//
+// An interface implemented by objects that expose their debugger display
+// attribute content through a property, making it possible for code to query
+// for the same content.
+//
+// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+
+namespace System.Threading.Tasks.Dataflow.Internal
+{
+    /// <summary>Implemented to provide customizable data for debugger displays.</summary>
+    internal interface IDebuggerDisplay
+    {
+        /// <summary>The object to be displayed as the content of a DebuggerDisplayAttribute.</summary>
+        /// <remarks>
+        /// The property returns an object to allow the debugger to interpret arbitrary .NET objects.
+        /// The return value may be, but need not be limited to be, a string.
+        /// </remarks>
+        object Content { get; }
+    }
+}