update readme.md

src/csharp/README.md

@@ -100,6 +100,12 @@ different languages.
 tools/run_tests/run_tests.py -l csharp
 ```
 
+ON .NET CORE SUPPORT
+------------------
+
+We are committed to providing full support for [.NET Core](https://dotnet.github.io/) in near future,
+but currently, the support is for .NET Core is experimental/work-in-progress.
+
 DOCUMENTATION
 -------------
 - the gRPC C# reference documentation is available online at [grpc.io][]