Change response buffering so it doesn't depend on policy

sdk/core/System.ClientModel/src/Convenience/ClientRequestException.cs

@@ -4,6 +4,7 @@
 using System.ClientModel.Internal;
 using System.ClientModel.Primitives;
 using System.Globalization;
+using System.IO;
 using System.Runtime.Serialization;
 using System.Text;
 using System.Threading;
@@ -79,7 +80,10 @@ private static string GetMessage(string? message, PipelineResponse? response)
             return DefaultMessage;
         }
 
-        ResponseBufferingPolicy.BufferContent(response, ResponseBufferingPolicy.DefaultNetworkTimeout, new CancellationTokenSource());
+        if (!response.TryGetBufferedContent(out _))
+        {
+            BufferResponse(response);
+        }
 
         StringBuilder messageBuilder = new();
 
@@ -103,4 +107,22 @@ private static string GetMessage(string? message, PipelineResponse? response)
 
         return messageBuilder.ToString();
     }
+
+    private static void BufferResponse(PipelineResponse response)
+    {
+        if (response.ContentStream is null)
+        {
+            return;
+        }
+
+        var bufferedStream = new MemoryStream();
+        response.ContentStream.CopyTo(bufferedStream);
+
+        // Dispose the unbuffered stream
+        response.ContentStream.Dispose();
+
+        // Reset the position of the buffered stream and set it on the response
+        bufferedStream.Position = 0;
+        response.ContentStream = bufferedStream;
+    }
 }

sdk/core/System.ClientModel/tests/System.ClientModel.Tests.csproj

@@ -8,13 +8,15 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="Microsoft.CSharp" />
     <PackageReference Include="Moq" />
     <PackageReference Include="NUnit" />
     <PackageReference Include="NUnit3TestAdapter" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" />
   </ItemGroup>
 
   <ItemGroup>
+    <ProjectReference Include="..\..\Azure.Core\src\Azure.Core.csproj" />
     <ProjectReference Include="..\src\System.ClientModel.csproj" />
     <ProjectReference Include="client\System.ClientModel.Tests.Client.csproj" />
   </ItemGroup>