renaming stub to client and refactoring metadata class
diff --git a/src/csharp/Grpc.Examples.MathClient/MathClient.cs b/src/csharp/Grpc.Examples.MathClient/MathClient.cs
index b763721..cfe2a06 100644
--- a/src/csharp/Grpc.Examples.MathClient/MathClient.cs
+++ b/src/csharp/Grpc.Examples.MathClient/MathClient.cs
@@ -41,18 +41,18 @@
         {
             using (Channel channel = new Channel("127.0.0.1", 23456))
             {
-                Math.IMathClient stub = new Math.MathClient(channel);
-                MathExamples.DivExample(stub);
+                Math.IMathClient client = new Math.MathClient(channel);
+                MathExamples.DivExample(client);
 
-                MathExamples.DivAsyncExample(stub).Wait();
+                MathExamples.DivAsyncExample(client).Wait();
 
-                MathExamples.FibExample(stub).Wait();
+                MathExamples.FibExample(client).Wait();
 
-                MathExamples.SumExample(stub).Wait();
+                MathExamples.SumExample(client).Wait();
 
-                MathExamples.DivManyExample(stub).Wait();
+                MathExamples.DivManyExample(client).Wait();
 
-                MathExamples.DependendRequestsExample(stub).Wait();
+                MathExamples.DependendRequestsExample(client).Wait();
             }
 
             GrpcEnvironment.Shutdown();