Use HttpRequestMessage.Options instead of Properties on net5.0

This dotnet/runtime PR marked Properties as obsolete:
dotnet/runtime#39182

Since we use warnings as errors, we have to change our code.

src/NuGet.Core/NuGet.Protocol/HttpSource/HttpRequestMessageExtensions.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Net;
 using System.Net.Http;
@@ -33,11 +34,18 @@ internal static HttpRequestMessage Clone(this HttpRequestMessage request)
                 clone.Headers.TryAddWithoutValidation(header.Key, header.Value);
             }
 
+#if NET5_0
+            var clonedOptions = (IDictionary<string, object>)clone.Options;
+            foreach (var option in request.Options)
+            {
+                clonedOptions.Add(option.Key, option.Value);
+            }
+#else
             foreach (var property in request.Properties)
             {
                 clone.Properties.Add(property);
             }
-
+#endif
             return clone;
         }
 
@@ -110,13 +118,22 @@ public static void SetConfiguration(this HttpRequestMessage request, HttpRequest
                 throw new ArgumentNullException(nameof(configuration));
             }
 
+#if NET5_0
+            request.Options.Set(new HttpRequestOptionsKey<HttpRequestMessageConfiguration>(NuGetConfigurationKey), configuration);
+#else
             request.Properties[NuGetConfigurationKey] = configuration;
+#endif
         }
 
         private static T GetProperty<T>(this HttpRequestMessage request, string key)
         {
+
+#if NET5_0
+            if (request.Options.TryGetValue<T>(new HttpRequestOptionsKey<T>(key), out T result))
+#else
             object result;
             if (request.Properties.TryGetValue(key, out result) && result is T)
+#endif
             {
                 return (T)result;
             }

src/NuGet.Core/NuGet.Protocol/HttpSource/HttpRetryHandler.cs

@@ -81,7 +81,11 @@ public async Task<HttpResponseMessage> SendAsync(
                         headerStopwatch = new Stopwatch();
                         stopwatches.Add(headerStopwatch);
                     }
+#if NET5_0
+                    requestMessage.Options.Set(new HttpRequestOptionsKey<List<Stopwatch>>(StopwatchPropertyName), stopwatches);
+#else
                     requestMessage.Properties[StopwatchPropertyName] = stopwatches;
+#endif
                     var requestUri = requestMessage.RequestUri;
 
                     try

src/NuGet.Core/NuGet.Protocol/HttpSource/HttpSourceAuthenticationHandler.cs

@@ -96,11 +96,18 @@ protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage
                 if (response.StatusCode == HttpStatusCode.Unauthorized ||
                     (configuration.PromptOn403 && response.StatusCode == HttpStatusCode.Forbidden))
                 {
-                    IList<Stopwatch> stopwatches = null;
+                    List<Stopwatch> stopwatches = null;
 
+#if NET5_0
+                    if (request.Options.TryGetValue(
+                        new HttpRequestOptionsKey<List<Stopwatch>>(HttpRetryHandler.StopwatchPropertyName),
+                        out stopwatches))
+                    {
+#else
                     if (request.Properties.TryGetValue(HttpRetryHandler.StopwatchPropertyName, out var value))
                     {
-                        stopwatches = value as IList<Stopwatch>;
+                        stopwatches = value as List<Stopwatch>;
+#endif
                         if (stopwatches != null)
                         {
                             foreach (var stopwatch in stopwatches)