Merge pull request #2797 from jtattermusch/polishing_api

src/csharp/Grpc.Core.Tests/ClientServerTest.cs

src/csharp/Grpc.Core.Tests/ServerTest.cs

src/csharp/Grpc.Core.Tests/TimeoutsTest.cs

src/csharp/Grpc.Core/ChannelOptions.cs

src/csharp/Grpc.Core/Grpc.Core.csproj

src/csharp/Grpc.Core/Grpc.Core.nuspec

src/csharp/Grpc.Core/Internal/ServerCredentialsSafeHandle.cs

src/csharp/Grpc.Core/KeyCertificatePair.cs

src/csharp/Grpc.Core/Metadata.cs

src/csharp/Grpc.Core/Server.cs

src/csharp/Grpc.Core/ServerCredentials.cs

src/csharp/Grpc.Core/ServerPort.cs

src/csharp/Grpc.Core/ServerServiceDefinition.cs

src/csharp/Grpc.Core/packages.config

src/csharp/Grpc.Examples.MathServer/MathServer.cs

src/csharp/Grpc.Examples.Tests/MathClientServerTests.cs

src/csharp/Grpc.HealthCheck.Tests/HealthClientServerTest.cs

...rp/Grpc.IntegrationTesting/Grpc.IntegrationTesting.csproj

...csharp/Grpc.IntegrationTesting/InteropClientServerTest.cs

src/csharp/Grpc.IntegrationTesting/InteropServer.cs