Replaced Dictionary with ConcurrentDictionary in HierarchicalLifetimeManager

Author: ENikS

src/Lifetime/HierarchicalLifetimeManager.cs

@@ -1,6 +1,5 @@
-// Copyright (c) Microsoft Corporation. All rights reserved. See License.txt in the project root for license information.
-
-using System;
+using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
 
@@ -16,7 +15,8 @@ public class HierarchicalLifetimeManager : SynchronizedLifetimeManager,
     {
         #region Fields
 
-        private readonly IDictionary<ILifetimeContainer, object> _values = new Dictionary<ILifetimeContainer, object>();
+        private readonly IDictionary<ILifetimeContainer, object> _values = 
+            new ConcurrentDictionary<ILifetimeContainer, object>();
 
         #endregion
 

src/Unity.Abstractions.csproj

@@ -22,6 +22,10 @@
     <RootNamespace>Unity</RootNamespace>
   </PropertyGroup>
 
+  <ItemGroup Condition="'$(TargetFramework)' != '' AND '$(TargetFramework)' != 'netstandard1.0' ">
+    <Compile Remove="Utility\ConcurrentDictionary.cs" />
+  </ItemGroup>
+
   <ItemGroup Condition="'$(TargetFramework)' != '' AND $(TargetFramework.StartsWith('netcoreapp'))">
     <Compile Remove="Exceptions\ResolutionFailedException.Desktop.cs" />
     <Compile Remove="Exceptions\IllegalInjectionMethodException.Desktop.cs" />