Imported Upstream version 3.6.0

Former-commit-id: da6be194a6b1221998fc28233f2503bd61dd9d14

external/aspnetwebstack/src/System.Web.Http/RouteParameter.cs

@@ -0,0 +1,36 @@
+// Copyright (c) Microsoft Corporation. All rights reserved. See License.txt in the project root for license information.
+
+using System.Diagnostics.CodeAnalysis;
+
+namespace System.Web.Http
+{
+    /// <summary>
+    /// The <see cref="RouteParameter"/> class can be used to indicate properties about a route parameter (the literals and placeholders 
+    /// located within segments of a <see cref="M:IHttpRoute.RouteTemplate"/>). 
+    /// It can for example be used to indicate that a route parameter is optional.
+    /// </summary>
+    public sealed class RouteParameter
+    {
+        /// <summary>
+        /// Optional Parameter
+        /// </summary>
+        [SuppressMessage("Microsoft.Security", "CA2104:DoNotDeclareReadOnlyMutableReferenceTypes", Justification = "This type is immutable.")]
+        public static readonly RouteParameter Optional = new RouteParameter();
+
+        // singleton constructor
+        private RouteParameter()
+        {
+        }
+
+        /// <summary>
+        /// Returns a <see cref="System.String"/> that represents this instance.
+        /// </summary>
+        /// <returns>
+        /// A <see cref="System.String"/> that represents this instance.
+        /// </returns>
+        public override string ToString()
+        {
+            return String.Empty;
+        }
+    }
+}