THRIFT-4990 Upgrade to .NET Core 3.1 (LTS)
Client: netstd
Patch: Jens Geyer

This closes #1961
diff --git a/test/netstd/Client/Program.cs b/test/netstd/Client/Program.cs
index 47dabd3..92000da 100644
--- a/test/netstd/Client/Program.cs
+++ b/test/netstd/Client/Program.cs
@@ -42,6 +42,7 @@
                     Console.WriteLine("The 'client' argument is no longer required.");
                     PrintHelp();
                     return -1;
+                case "--performance":
                 case "--performance-test":
                     return Tests.PerformanceTests.Execute();
                 case "--help":