Reworked GrpcEnvironment initialization and shutdown to allow running all tests at once.
diff --git a/src/csharp/GrpcApiTests/MathClientServerTests.cs b/src/csharp/GrpcApiTests/MathClientServerTests.cs
index 9b51924..7654ec8 100644
--- a/src/csharp/GrpcApiTests/MathClientServerTests.cs
+++ b/src/csharp/GrpcApiTests/MathClientServerTests.cs
@@ -21,6 +21,8 @@
         [TestFixtureSetUp]
         public void Init()
         {
+            GrpcEnvironment.Initialize();
+
             server = new Server();
             server.AddServiceDefinition(MathGrpc.BindService(new MathServiceImpl()));
             int port = server.AddPort(host + ":0");