Improve Json perf by using JObject.Load.

Author: livarcocc

src/Microsoft.DotNet.Cli.Utils/RuntimeConfig.cs

@@ -1,8 +1,9 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved. 
 // Licensed under the MIT license. See LICENSE file in the project root for full license information. 
- 
+
+using Newtonsoft.Json;
 using Newtonsoft.Json.Linq; 
-using System.IO; 
+using System.IO;
 
 namespace Microsoft.DotNet.Cli.Utils
 { 
@@ -32,8 +33,10 @@ public static bool IsApplicationPortable(string entryAssemblyPath)
         } 
 
         private JObject OpenRuntimeConfig(string runtimeConfigPath) 
-        { 
-            return JObject.Parse(File.ReadAllText(runtimeConfigPath)); 
+        {
+            var reader = new JsonTextReader(new StringReader(File.ReadAllText(runtimeConfigPath)));
+
+            return JObject.Load(reader);
         } 
 
         private RuntimeConfigFramework ParseFramework(JObject runtimeConfigRoot) 

src/dotnet/commands/dotnet-add/dotnet-add-package/AddPackageParser.cs

@@ -3,10 +3,12 @@
 
 using System;
 using System.Collections.Generic;
+using System.IO;
 using System.Linq;
 using System.Net.Http;
 using System.Threading;
 using Microsoft.DotNet.Cli.CommandLine;
+using Newtonsoft.Json;
 using Newtonsoft.Json.Linq;
 using LocalizableStrings = Microsoft.DotNet.Tools.Add.PackageReference.LocalizableStrings;
 
@@ -67,11 +69,14 @@ public static IEnumerable<string> QueryNuGet(string match)
                 yield break;
             }
 
-            var json = JObject.Parse(result);
-
-            foreach (var id in json["data"])
+            using (var reader = new JsonTextReader(new StringReader(result)))
             {
-                yield return id["id"].Value<string>();
+                var json = JObject.Load(reader);
+
+                foreach (var id in json["data"])
+                {
+                    yield return id["id"].Value<string>();
+                }
             }
         }
     }