THRIFT-5216 generate DeepCopy methods
Client: netstd
Patch: Jens Geyer

This closes #2155
diff --git a/lib/netstd/Thrift/Protocol/TBase.cs b/lib/netstd/Thrift/Protocol/TBase.cs
index b5ef2ae..df9dd34 100644
--- a/lib/netstd/Thrift/Protocol/TBase.cs
+++ b/lib/netstd/Thrift/Protocol/TBase.cs
@@ -22,12 +22,13 @@
 {
     public interface TUnionBase
     {
-        Task WriteAsync(TProtocol tProtocol, CancellationToken cancellationToken = default(CancellationToken));
+        Task WriteAsync(TProtocol tProtocol, CancellationToken cancellationToken = default);
     }
 
     // ReSharper disable once InconsistentNaming
     public interface TBase : TUnionBase
     {
-        Task ReadAsync(TProtocol tProtocol, CancellationToken cancellationToken = default(CancellationToken));
+        Task ReadAsync(TProtocol tProtocol, CancellationToken cancellationToken = default);
     }
+
 }