Merge branch 'master' of github.com:grpc/grpc into grpclb_api

44 files changed, 1140 insertions, 380 deletions

diff --git a/src/csharp/Grpc.Auth/GoogleAuthInterceptors.cs b/src/csharp/Grpc.Auth/GoogleAuthInterceptors.cs
index 1c14c5bb5b..f77e9c6573 100644
--- a/src/csharp/Grpc.Auth/GoogleAuthInterceptors.cs
+++ b/src/csharp/Grpc.Auth/GoogleAuthInterceptors.cs
@@ -57,9 +57,9 @@ namespace Grpc.Auth
         /// <returns>The interceptor.</returns>
         public static AsyncAuthInterceptor FromCredential(ITokenAccess credential)
         {
-            return new AsyncAuthInterceptor(async (authUri, metadata) =>
+            return new AsyncAuthInterceptor(async (context, metadata) =>
             {
-                var accessToken = await credential.GetAccessTokenForRequestAsync(authUri, CancellationToken.None).ConfigureAwait(false);
+                var accessToken = await credential.GetAccessTokenForRequestAsync(context.ServiceUrl, CancellationToken.None).ConfigureAwait(false);
                 metadata.Add(CreateBearerTokenHeader(accessToken));
             });
         }
@@ -72,7 +72,7 @@ namespace Grpc.Auth
         public static AsyncAuthInterceptor FromAccessToken(string accessToken)
         {
             Preconditions.CheckNotNull(accessToken);
-            return new AsyncAuthInterceptor(async (authUri, metadata) =>
+            return new AsyncAuthInterceptor(async (context, metadata) =>
             {
                 metadata.Add(CreateBearerTokenHeader(accessToken));
             });
diff --git a/src/csharp/Grpc.Core.Tests/CallOptionsTest.cs b/src/csharp/Grpc.Core.Tests/CallOptionsTest.cs
new file mode 100644
index 0000000000..a3a613be74
--- /dev/null
+++ b/src/csharp/Grpc.Core.Tests/CallOptionsTest.cs
@@ -0,0 +1,88 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using Grpc.Core;
+using Grpc.Core.Internal;
+using Grpc.Core.Utils;
+using NUnit.Framework;
+
+namespace Grpc.Core.Tests
+{
+    public class CallOptionsTest
+    {
+        [Test]
+        public void WithMethods()
+        {
+            var options = new CallOptions();
+            
+            var metadata = new Metadata();
+            Assert.AreSame(metadata, options.WithHeaders(metadata).Headers);
+
+            var deadline = DateTime.UtcNow;
+            Assert.AreEqual(deadline, options.WithDeadline(deadline).Deadline.Value);
+
+            var token = new CancellationTokenSource().Token;
+            Assert.AreEqual(token, options.WithCancellationToken(token).CancellationToken);
+
+            // Change original instance is unchanged.
+            Assert.IsNull(options.Headers);
+            Assert.IsNull(options.Deadline);
+            Assert.AreEqual(CancellationToken.None, options.CancellationToken);
+            Assert.IsNull(options.WriteOptions);
+            Assert.IsNull(options.PropagationToken);
+            Assert.IsNull(options.Credentials);
+        }
+
+        [Test]
+        public void Normalize()
+        {
+            Assert.AreSame(Metadata.Empty, new CallOptions().Normalize().Headers);
+            Assert.AreEqual(DateTime.MaxValue, new CallOptions().Normalize().Deadline.Value);
+
+            var deadline = DateTime.UtcNow;
+            var propagationToken1 = new ContextPropagationToken(CallSafeHandle.NullInstance, deadline, CancellationToken.None,
+                new ContextPropagationOptions(propagateDeadline: true, propagateCancellation: false));
+            Assert.AreEqual(deadline, new CallOptions(propagationToken: propagationToken1).Normalize().Deadline.Value);
+            Assert.Throws(typeof(ArgumentException), () => new CallOptions(deadline: deadline, propagationToken: propagationToken1).Normalize());
+
+            var token = new CancellationTokenSource().Token;
+            var propagationToken2 = new ContextPropagationToken(CallSafeHandle.NullInstance, deadline, token,
+                new ContextPropagationOptions(propagateDeadline: false, propagateCancellation: true));
+            Assert.AreEqual(token, new CallOptions(propagationToken: propagationToken2).Normalize().CancellationToken);
+            Assert.Throws(typeof(ArgumentException), () => new CallOptions(cancellationToken: token, propagationToken: propagationToken2).Normalize());
+        }
+    }
+}
diff --git a/src/csharp/Grpc.Core.Tests/ChannelOptionsTest.cs b/src/csharp/Grpc.Core.Tests/ChannelOptionsTest.cs
index 52be77c846..d2b5a436fd 100644
--- a/src/csharp/Grpc.Core.Tests/ChannelOptionsTest.cs
+++ b/src/csharp/Grpc.Core.Tests/ChannelOptionsTest.cs
@@ -38,7 +38,7 @@ using Grpc.Core.Internal;
 using Grpc.Core.Utils;
 using NUnit.Framework;
 
-namespace Grpc.Core.Internal.Tests
+namespace Grpc.Core.Tests
 {
     public class ChannelOptionsTest
     {
diff --git a/src/csharp/Grpc.Core.Tests/ChannelTest.cs b/src/csharp/Grpc.Core.Tests/ChannelTest.cs
index f4ae9abefd..ed0ec14df5 100644
--- a/src/csharp/Grpc.Core.Tests/ChannelTest.cs
+++ b/src/csharp/Grpc.Core.Tests/ChannelTest.cs
@@ -48,6 +48,17 @@ namespace Grpc.Core.Tests
         }
 
         [Test]
+        public void Constructor_RejectsDuplicateOptions()
+        {
+            var options = new ChannelOption[]
+            {
+                new ChannelOption(ChannelOptions.PrimaryUserAgentString, "ABC"),
+                new ChannelOption(ChannelOptions.PrimaryUserAgentString, "XYZ")
+            };
+            Assert.Throws(typeof(ArgumentException), () => new Channel("127.0.0.1", ChannelCredentials.Insecure, options));
+        }
+
+        [Test]
         public void State_IdleAfterCreation()
         {
             var channel = new Channel("localhost", ChannelCredentials.Insecure);
diff --git a/src/csharp/Grpc.Core.Tests/ClientServerTest.cs b/src/csharp/Grpc.Core.Tests/ClientServerTest.cs
index 25a5a27c8e..77f6a63156 100644
--- a/src/csharp/Grpc.Core.Tests/ClientServerTest.cs
+++ b/src/csharp/Grpc.Core.Tests/ClientServerTest.cs
@@ -32,6 +32,7 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
 using System.Threading;
@@ -144,6 +145,45 @@ namespace Grpc.Core.Tests
             var call = Calls.AsyncClientStreamingCall(helper.CreateClientStreamingCall());
             await call.RequestStream.WriteAllAsync(new string[] { "A", "B", "C" });
             Assert.AreEqual("ABC", await call.ResponseAsync);
+
+            Assert.AreEqual(StatusCode.OK, call.GetStatus().StatusCode);
+            Assert.IsNotNull(call.GetTrailers());
+        }
+
+        [Test]
+        public async Task ServerStreamingCall()
+        {
+            helper.ServerStreamingHandler = new ServerStreamingServerMethod<string, string>(async (request, responseStream, context) =>
+            {
+                await responseStream.WriteAllAsync(request.Split(new []{' '}));
+                context.ResponseTrailers.Add("xyz", "");
+            });
+
+            var call = Calls.AsyncServerStreamingCall(helper.CreateServerStreamingCall(), "A B C");
+            CollectionAssert.AreEqual(new string[] { "A", "B", "C" }, await call.ResponseStream.ToListAsync());
+
+            Assert.AreEqual(StatusCode.OK, call.GetStatus().StatusCode);
+            Assert.IsNotNull("xyz", call.GetTrailers()[0].Key);
+        }
+
+        [Test]
+        public async Task DuplexStreamingCall()
+        {
+            helper.DuplexStreamingHandler = new DuplexStreamingServerMethod<string, string>(async (requestStream, responseStream, context) =>
+            {
+                while (await requestStream.MoveNext())
+                {
+                    await responseStream.WriteAsync(requestStream.Current);
+                }
+                context.ResponseTrailers.Add("xyz", "xyz-value");
+            });
+
+            var call = Calls.AsyncDuplexStreamingCall(helper.CreateDuplexStreamingCall());
+            await call.RequestStream.WriteAllAsync(new string[] { "A", "B", "C" });
+            CollectionAssert.AreEqual(new string[] { "A", "B", "C" }, await call.ResponseStream.ToListAsync());
+
+            Assert.AreEqual(StatusCode.OK, call.GetStatus().StatusCode);
+            Assert.IsNotNull("xyz-value", call.GetTrailers()[0].Value);
         }
 
         [Test]
@@ -201,7 +241,7 @@ namespace Grpc.Core.Tests
             Assert.AreEqual(headers[1].Key, trailers[1].Key);
             CollectionAssert.AreEqual(headers[1].ValueBytes, trailers[1].ValueBytes);
         }
-            
+
         [Test]
         public void UnknownMethodHandler()
         {
@@ -219,27 +259,27 @@ namespace Grpc.Core.Tests
         }
 
         [Test]
-        public void UserAgentStringPresent()
+        public void ServerCallContext_PeerInfoPresent()
         {
             helper.UnaryHandler = new UnaryServerMethod<string, string>(async (request, context) =>
             {
-                return context.RequestHeaders.Where(entry => entry.Key == "user-agent").Single().Value;
+                return context.Peer;
             });
 
-            string userAgent = Calls.BlockingUnaryCall(helper.CreateUnaryCall(), "abc");
-            Assert.IsTrue(userAgent.StartsWith("grpc-csharp/"));
+            string peer = Calls.BlockingUnaryCall(helper.CreateUnaryCall(), "abc");
+            Assert.IsTrue(peer.Contains(Host));
         }
 
         [Test]
-        public void PeerInfoPresent()
+        public void ServerCallContext_HostAndMethodPresent()
         {
             helper.UnaryHandler = new UnaryServerMethod<string, string>(async (request, context) =>
             {
-                return context.Peer;
+                Assert.IsTrue(context.Host.Contains(Host));
+                Assert.AreEqual("/tests.Test/Unary", context.Method);
+                return "PASS";
             });
-
-            string peer = Calls.BlockingUnaryCall(helper.CreateUnaryCall(), "abc");
-            Assert.IsTrue(peer.Contains(Host));
+            Assert.AreEqual("PASS", Calls.BlockingUnaryCall(helper.CreateUnaryCall(), "abc"));
         }
 
         [Test]
diff --git a/src/csharp/Grpc.Core.Tests/ContextPropagationTest.cs b/src/csharp/Grpc.Core.Tests/ContextPropagationTest.cs
index 2db3f286f7..90c510ec61 100644
--- a/src/csharp/Grpc.Core.Tests/ContextPropagationTest.cs
+++ b/src/csharp/Grpc.Core.Tests/ContextPropagationTest.cs
@@ -69,11 +69,19 @@ namespace Grpc.Core.Tests
         [Test]
         public async Task PropagateCancellation()
         {
+            var readyToCancelTcs = new TaskCompletionSource<object>();
+            var successTcs = new TaskCompletionSource<string>();
+
             helper.UnaryHandler = new UnaryServerMethod<string, string>(async (request, context) =>
             {
-                // check that we didn't obtain the default cancellation token.
-                Assert.IsTrue(context.CancellationToken.CanBeCanceled);
-                return "PASS";
+                readyToCancelTcs.SetResult(null);  // child call running, ready to parent call
+
+                while (!context.CancellationToken.IsCancellationRequested)
+                {
+                    await Task.Delay(10);
+                }
+                successTcs.SetResult("CHILD_CALL_CANCELLED");
+                return "";
             });
 
             helper.ClientStreamingHandler = new ClientStreamingServerMethod<string, string>(async (requestStream, context) =>
@@ -82,13 +90,23 @@ namespace Grpc.Core.Tests
                 Assert.IsNotNull(propagationToken.ParentCall);
 
                 var callOptions = new CallOptions(propagationToken: propagationToken);
-                return await Calls.AsyncUnaryCall(helper.CreateUnaryCall(callOptions), "xyz");
+                try
+                {
+                    await Calls.AsyncUnaryCall(helper.CreateUnaryCall(callOptions), "xyz");
+                }
+                catch(RpcException)
+                {
+                    // Child call will get cancelled, eat the exception.
+                }
+                return "";
             });
                 
             var cts = new CancellationTokenSource();
-            var call = Calls.AsyncClientStreamingCall(helper.CreateClientStreamingCall(new CallOptions(cancellationToken: cts.Token)));
-            await call.RequestStream.CompleteAsync();
-            Assert.AreEqual("PASS", await call);
+            var parentCall = Calls.AsyncClientStreamingCall(helper.CreateClientStreamingCall(new CallOptions(cancellationToken: cts.Token)));
+            await readyToCancelTcs.Task;
+            cts.Cancel();
+            Assert.Throws(typeof(RpcException), async () => await parentCall);
+            Assert.AreEqual("CHILD_CALL_CANCELLED", await successTcs.Task);
         }
 
         [Test]
diff --git a/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj b/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj
index e5ffa31989..475c792347 100644
--- a/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj
+++ b/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj
@@ -64,6 +64,8 @@
       <Link>Version.cs</Link>
     </Compile>
     <Compile Include="CallCredentialsTest.cs" />
+    <Compile Include="CallOptionsTest.cs" />
+    <Compile Include="UserAgentStringTest.cs" />
     <Compile Include="FakeCredentials.cs" />
     <Compile Include="MarshallingErrorsTest.cs" />
     <Compile Include="ChannelCredentialsTest.cs" />
@@ -89,6 +91,7 @@
     <Compile Include="ContextPropagationTest.cs" />
     <Compile Include="MetadataTest.cs" />
     <Compile Include="PerformanceTest.cs" />
+    <Compile Include="SanityTest.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <ItemGroup>
diff --git a/src/csharp/Grpc.Core.Tests/Internal/TimespecTest.cs b/src/csharp/Grpc.Core.Tests/Internal/TimespecTest.cs
index 9be5450d81..74f7f2497a 100644
--- a/src/csharp/Grpc.Core.Tests/Internal/TimespecTest.cs
+++ b/src/csharp/Grpc.Core.Tests/Internal/TimespecTest.cs
@@ -82,17 +82,17 @@ namespace Grpc.Core.Internal.Tests
         public void ToDateTime()
         {
             Assert.AreEqual(new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc),
-                new Timespec(IntPtr.Zero, 0).ToDateTime());
+                new Timespec(0, 0).ToDateTime());
 
             Assert.AreEqual(new DateTime(1970, 1, 1, 0, 0, 10, DateTimeKind.Utc).AddTicks(50),
-                new Timespec(new IntPtr(10), 5000).ToDateTime());
+                new Timespec(10, 5000).ToDateTime());
 
             Assert.AreEqual(new DateTime(2015, 7, 21, 4, 21, 48, DateTimeKind.Utc),
-                new Timespec(new IntPtr(1437452508), 0).ToDateTime());
+                new Timespec(1437452508, 0).ToDateTime());
 
             // before epoch
             Assert.AreEqual(new DateTime(1969, 12, 31, 23, 59, 55, DateTimeKind.Utc).AddTicks(10),
-                new Timespec(new IntPtr(-5), 1000).ToDateTime());
+                new Timespec(-5, 1000).ToDateTime());
 
             // infinity
             Assert.AreEqual(DateTime.MaxValue, Timespec.InfFuture.ToDateTime());
@@ -100,80 +100,62 @@ namespace Grpc.Core.Internal.Tests
 
             // nanos are rounded to ticks are rounded up
             Assert.AreEqual(new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc).AddTicks(1),
-                new Timespec(IntPtr.Zero, 99).ToDateTime());
+                new Timespec(0, 99).ToDateTime());
 
             // Illegal inputs
             Assert.Throws(typeof(InvalidOperationException),
-                () => new Timespec(new IntPtr(0), -2).ToDateTime());
+                () => new Timespec(0, -2).ToDateTime());
             Assert.Throws(typeof(InvalidOperationException),
-                () => new Timespec(new IntPtr(0), 1000 * 1000 * 1000).ToDateTime());
+                () => new Timespec(0, 1000 * 1000 * 1000).ToDateTime());
             Assert.Throws(typeof(InvalidOperationException),
-                () => new Timespec(new IntPtr(0), 0, GPRClockType.Monotonic).ToDateTime());
+                () => new Timespec(0, 0, GPRClockType.Monotonic).ToDateTime());
         }
 
         [Test]
         public void ToDateTime_ReturnsUtc()
         {
-            Assert.AreEqual(DateTimeKind.Utc, new Timespec(new IntPtr(1437452508), 0).ToDateTime().Kind);
-            Assert.AreNotEqual(DateTimeKind.Unspecified, new Timespec(new IntPtr(1437452508), 0).ToDateTime().Kind);
+            Assert.AreEqual(DateTimeKind.Utc, new Timespec(1437452508, 0).ToDateTime().Kind);
+            Assert.AreNotEqual(DateTimeKind.Unspecified, new Timespec(1437452508, 0).ToDateTime().Kind);
         }
 
         [Test]
         public void ToDateTime_Overflow()
-        {
-            // we can only get overflow in ticks arithmetic on 64-bit
-            if (IntPtr.Size == 8)
-            {
-                var timespec = new Timespec(new IntPtr(long.MaxValue - 100), 0);
-                Assert.AreNotEqual(Timespec.InfFuture, timespec);
-                Assert.AreEqual(DateTime.MaxValue, timespec.ToDateTime());
-
-                Assert.AreEqual(DateTime.MinValue, new Timespec(new IntPtr(long.MinValue + 100), 0).ToDateTime());
-            }
-            else
-            {
-                Console.WriteLine("Test cannot be run on this platform, skipping the test.");
-            }
+        {     
+            var timespec = new Timespec(long.MaxValue - 100, 0);
+            Assert.AreNotEqual(Timespec.InfFuture, timespec);
+            Assert.AreEqual(DateTime.MaxValue, timespec.ToDateTime());
+
+            Assert.AreEqual(DateTime.MinValue, new Timespec(long.MinValue + 100, 0).ToDateTime());
         }
 
         [Test]
         public void ToDateTime_OutOfDateTimeRange()
         {
-            // we can only get out of range on 64-bit, on 32 bit the max 
-            // timestamp is ~ Jan 19 2038, which is far within range of DateTime
-            // same case for min value.
-            if (IntPtr.Size == 8)
-            {
-                // DateTime range goes up to year 9999, 20000 years from now should
-                // be out of range.
-                long seconds = 20000L * 365L * 24L * 3600L; 
-
-                var timespec = new Timespec(new IntPtr(seconds), 0);
-                Assert.AreNotEqual(Timespec.InfFuture, timespec);
-                Assert.AreEqual(DateTime.MaxValue, timespec.ToDateTime());
-
-                Assert.AreEqual(DateTime.MinValue, new Timespec(new IntPtr(-seconds), 0).ToDateTime());
-            }
-            else
-            {
-                Console.WriteLine("Test cannot be run on this platform, skipping the test");
-            }
+            // DateTime range goes up to year 9999, 20000 years from now should
+            // be out of range.
+            long seconds = 20000L * 365L * 24L * 3600L; 
+
+            var timespec = new Timespec(seconds, 0);
+            Assert.AreNotEqual(Timespec.InfFuture, timespec);
+            Assert.AreEqual(DateTime.MaxValue, timespec.ToDateTime());
+
+            Assert.AreEqual(DateTime.MinValue, new Timespec(-seconds, 0).ToDateTime());
         }
 
         [Test]
         public void FromDateTime()
         {
-            Assert.AreEqual(new Timespec(IntPtr.Zero, 0),
+            Assert.AreEqual(new Timespec(0, 0),
                 Timespec.FromDateTime(new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc)));
 
-            Assert.AreEqual(new Timespec(new IntPtr(10), 5000),
+            Assert.AreEqual(new Timespec(10, 5000),
                 Timespec.FromDateTime(new DateTime(1970, 1, 1, 0, 0, 10, DateTimeKind.Utc).AddTicks(50)));
 
-            Assert.AreEqual(new Timespec(new IntPtr(1437452508), 0),
+            Assert.AreEqual(new Timespec(1437452508, 0),
                 Timespec.FromDateTime(new DateTime(2015, 7, 21, 4, 21, 48, DateTimeKind.Utc)));
 
             // before epoch
-            Assert.AreEqual(new Timespec(new IntPtr(-5), 1000),
+            Assert.AreEqual(new Timespec(-5, 1000),
                 Timespec.FromDateTime(new DateTime(1969, 12, 31, 23, 59, 55, DateTimeKind.Utc).AddTicks(10)));
 
             // infinity
@@ -184,34 +166,19 @@ namespace Grpc.Core.Internal.Tests
             Assert.Throws(typeof(ArgumentException),
                 () => Timespec.FromDateTime(new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Unspecified)));
         }
-
-        [Test]
-        public void FromDateTime_OutOfTimespecRange()
-        {
-            // we can only get overflow in Timespec on 32-bit
-            if (IntPtr.Size == 4)
-            {
-                Assert.AreEqual(Timespec.InfFuture, Timespec.FromDateTime(new DateTime(2040, 1, 1, 0, 0, 0, DateTimeKind.Utc)));
-                Assert.AreEqual(Timespec.InfPast, Timespec.FromDateTime(new DateTime(1800, 1, 1, 0, 0, 0, DateTimeKind.Utc)));
-            }
-            else
-            {
-                Console.WriteLine("Test cannot be run on this platform, skipping the test.");
-            }
-        }
             
-        // Test attribute commented out to prevent running as part of the default test suite.
-        // [Test]
-        // [Category("Performance")]
+        [Test]
+        [Category("Performance")]
+        [Ignore("Prevent running on Jenkins")]
         public void NowBenchmark() 
         {
             // approx Timespec.Now latency <33ns
             BenchmarkUtil.RunBenchmark(10000000, 1000000000, () => { var now = Timespec.Now; });
         }
-
-        // Test attribute commented out to prevent running as part of the default test suite.
-        // [Test]
-        // [Category("Performance")]
+            
+        [Test]
+        [Category("Performance")]
+        [Ignore("Prevent running on Jenkins")]
         public void PreciseNowBenchmark()
         {
             // approx Timespec.PreciseNow latency <18ns (when compiled with GRPC_TIMERS_RDTSC)
diff --git a/src/csharp/Grpc.Core.Tests/MetadataTest.cs b/src/csharp/Grpc.Core.Tests/MetadataTest.cs
index ddeb7d0926..49e9de1174 100644
--- a/src/csharp/Grpc.Core.Tests/MetadataTest.cs
+++ b/src/csharp/Grpc.Core.Tests/MetadataTest.cs
@@ -127,5 +127,118 @@ namespace Grpc.Core.Tests
             Assert.Throws(typeof(InvalidOperationException), () => { var v = entry.Value; });
             CollectionAssert.AreEqual(bytes, entry.ValueBytes);
         }
+
+        [Test]
+        public void IndexOf()
+        {
+            var metadata = CreateMetadata();
+            Assert.AreEqual(0, metadata.IndexOf(metadata[0]));
+            Assert.AreEqual(1, metadata.IndexOf(metadata[1]));
+        }
+
+        [Test]
+        public void Insert()
+        {
+            var metadata = CreateMetadata();
+            metadata.Insert(0, new Metadata.Entry("new-key", "new-value"));
+            Assert.AreEqual(3, metadata.Count);
+            Assert.AreEqual("new-key", metadata[0].Key);
+            Assert.AreEqual("abc", metadata[1].Key);
+        }
+
+        [Test]
+        public void RemoveAt()
+        {
+            var metadata = CreateMetadata();
+            metadata.RemoveAt(0);
+            Assert.AreEqual(1, metadata.Count);
+            Assert.AreEqual("xyz", metadata[0].Key);
+        }
+
+        [Test]
+        public void Remove()
+        {
+            var metadata = CreateMetadata();
+            metadata.Remove(metadata[0]);
+            Assert.AreEqual(1, metadata.Count);
+            Assert.AreEqual("xyz", metadata[0].Key);
+        }
+
+        [Test]
+        public void Indexer_Set()
+        {
+            var metadata = CreateMetadata();
+            var entry = new Metadata.Entry("new-key", "new-value");
+
+            metadata[1] = entry;
+            Assert.AreEqual(entry, metadata[1]);
+        }
+
+        [Test]
+        public void Clear()
+        {
+            var metadata = CreateMetadata();
+            metadata.Clear();
+            Assert.AreEqual(0, metadata.Count);
+        }
+
+        [Test]
+        public void Contains()
+        {
+            var metadata = CreateMetadata();
+            Assert.IsTrue(metadata.Contains(metadata[0]));
+            Assert.IsFalse(metadata.Contains(new Metadata.Entry("new-key", "new-value")));
+        }
+
+        [Test]
+        public void CopyTo()
+        {
+            var metadata = CreateMetadata();
+            var array = new Metadata.Entry[metadata.Count + 1];
+
+            metadata.CopyTo(array, 1);
+            Assert.AreEqual(default(Metadata.Entry), array[0]);
+            Assert.AreEqual(metadata[0], array[1]);
+        }
+
+        [Test]
+        public void IEnumerableGetEnumerator()
+        {
+            var metadata = CreateMetadata();
+            var enumerator = (metadata as System.Collections.IEnumerable).GetEnumerator();
+            
+            int i = 0;
+            while (enumerator.MoveNext())
+            {
+                Assert.AreEqual(metadata[i], enumerator.Current);
+                i++;
+            }
+        }
+
+        [Test]
+        public void FreezeMakesReadOnly()
+        {
+            var entry = new Metadata.Entry("new-key", "new-value");
+            var metadata = CreateMetadata().Freeze();
+
+            Assert.IsTrue(metadata.IsReadOnly);
+            Assert.Throws<InvalidOperationException>(() => metadata.Insert(0, entry));
+            Assert.Throws<InvalidOperationException>(() => metadata.RemoveAt(0));
+            Assert.Throws<InvalidOperationException>(() => metadata[0] = entry);
+            Assert.Throws<InvalidOperationException>(() => metadata.Add(entry));
+            Assert.Throws<InvalidOperationException>(() => metadata.Add("new-key", "new-value"));
+            Assert.Throws<InvalidOperationException>(() => metadata.Add("new-key-bin", new byte[] { 0xaa }));
+            Assert.Throws<InvalidOperationException>(() => metadata.Clear());
+            Assert.Throws<InvalidOperationException>(() => metadata.Remove(metadata[0]));
+        }
+
+        private Metadata CreateMetadata()
+        {
+            return new Metadata
+            {
+                { "abc", "abc-value" },
+                { "xyz", "xyz-value" },
+            };
+        }
     }
 }
diff --git a/src/csharp/Grpc.Core.Tests/MockServiceHelper.cs b/src/csharp/Grpc.Core.Tests/MockServiceHelper.cs
index 567e04eddc..3047314345 100644
--- a/src/csharp/Grpc.Core.Tests/MockServiceHelper.cs
+++ b/src/csharp/Grpc.Core.Tests/MockServiceHelper.cs
@@ -32,6 +32,7 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
 using System.Threading;
@@ -52,6 +53,7 @@ namespace Grpc.Core.Tests
 
         readonly string host;
         readonly ServerServiceDefinition serviceDefinition;
+        readonly IEnumerable<ChannelOption> channelOptions;
 
         readonly Method<string, string> unaryMethod;
         readonly Method<string, string> clientStreamingMethod;
@@ -66,9 +68,10 @@ namespace Grpc.Core.Tests
         Server server;
         Channel channel;
 
-        public MockServiceHelper(string host = null, Marshaller<string> marshaller = null)
+        public MockServiceHelper(string host = null, Marshaller<string> marshaller = null, IEnumerable<ChannelOption> channelOptions = null)
         {
             this.host = host ?? "localhost";
+            this.channelOptions = channelOptions;
             marshaller = marshaller ?? Marshallers.StringMarshaller;
 
             unaryMethod = new Method<string, string>(
@@ -154,7 +157,7 @@ namespace Grpc.Core.Tests
         {
             if (channel == null)
             {
-                channel = new Channel(Host, GetServer().Ports.Single().BoundPort, ChannelCredentials.Insecure);
+                channel = new Channel(Host, GetServer().Ports.Single().BoundPort, ChannelCredentials.Insecure, channelOptions);
             }
             return channel;
         }
diff --git a/src/csharp/Grpc.Core.Tests/PInvokeTest.cs b/src/csharp/Grpc.Core.Tests/PInvokeTest.cs
index 073c502daf..af55cb0566 100644
--- a/src/csharp/Grpc.Core.Tests/PInvokeTest.cs
+++ b/src/csharp/Grpc.Core.Tests/PInvokeTest.cs
@@ -59,6 +59,8 @@ namespace Grpc.Core.Tests
         [Test]
         public void CompletionQueueCreateDestroyBenchmark()
         {
+            GrpcEnvironment.AddRef();  // completion queue requires gRPC environment being initialized.
+
             BenchmarkUtil.RunBenchmark(
                 10, 10,
                 () =>
@@ -66,6 +68,8 @@ namespace Grpc.Core.Tests
                     CompletionQueueSafeHandle cq = CompletionQueueSafeHandle.Create();
                     cq.Dispose();
                 });
+
+            GrpcEnvironment.Release();
         }
 
         /// <summary>
diff --git a/src/csharp/Grpc.Core.Tests/PerformanceTest.cs b/src/csharp/Grpc.Core.Tests/PerformanceTest.cs
index 5516cd3377..6815839992 100644
--- a/src/csharp/Grpc.Core.Tests/PerformanceTest.cs
+++ b/src/csharp/Grpc.Core.Tests/PerformanceTest.cs
@@ -67,10 +67,10 @@ namespace Grpc.Core.Tests
             channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
         }
-
-        // Test attribute commented out to prevent running as part of the default test suite.
-        //[Test]
-        //[Category("Performance")]
+            
+        [Test]
+        [Category("Performance")]
+        [Ignore("Prevent running on Jenkins")]
         public void UnaryCallPerformance()
         {
             var profiler = new BasicProfiler();
diff --git a/src/csharp/Grpc.Core.Tests/SanityTest.cs b/src/csharp/Grpc.Core.Tests/SanityTest.cs
new file mode 100644
index 0000000000..343ab1e85a
--- /dev/null
+++ b/src/csharp/Grpc.Core.Tests/SanityTest.cs
@@ -0,0 +1,125 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Reflection;
+using Grpc.Core;
+using Grpc.Core.Internal;
+using Grpc.Core.Utils;
+using NUnit.Framework;
+
+namespace Grpc.Core.Tests
+{
+    public class SanityTest
+    {
+        /// <summary>
+        /// Because we depend on a native library, sometimes when things go wrong, the
+        /// entire NUnit test process crashes. To be able to track down problems better,
+        /// the NUnit tests are run by run_tests.py script in a separate process per test class.
+        /// The list of tests to run is stored in src/csharp/tests.json.
+        /// This test checks that the tests.json file is up to date by discovering all the
+        /// existing NUnit tests in all test assemblies and comparing to contents of tests.json.
+        /// </summary>
+        [Test]
+        public void TestsJsonUpToDate()
+        {
+            var testClasses = DiscoverAllTestClasses();
+            string testsJson = GetTestsJson();
+
+            // we don't have a JSON parser at hand, but check that the test class
+            // name is contained in the file instead.
+            foreach (var className in testClasses) {
+                Assert.IsTrue(testsJson.Contains(className),
+                    string.Format("Test class \"{0}\" is missing in C# tests.json file", className));
+            }
+        }
+
+        /// <summary>
+        /// Gets list of all test classes obtained by inspecting all the test assemblies.
+        /// </summary>
+        private List<string> DiscoverAllTestClasses()
+        {
+            var assemblies = GetTestAssemblies();
+
+            var testClasses = new List<string>();
+            foreach (var assembly in assemblies)
+            {
+                foreach (var t in assembly.GetTypes())
+                {
+                    foreach (var m in t.GetMethods())
+                    {
+                        var attributes = m.GetCustomAttributes(typeof(NUnit.Framework.TestAttribute), true);
+                        if (attributes.Length > 0)
+                        {
+                            testClasses.Add(t.FullName);
+                            break;
+                        }
+
+                    }
+                }
+            }
+            testClasses.Sort();
+            return testClasses;
+        }
+
+        private string GetTestsJson()
+        {
+            var assemblyDir = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
+            var testsJsonFile = Path.Combine(assemblyDir, "..", "..", "..", "tests.json");
+
+            return File.ReadAllText(testsJsonFile);
+        }
+
+        private List<Assembly> GetTestAssemblies()
+        {
+            var result = new List<Assembly>();
+            var executingAssembly = Assembly.GetExecutingAssembly();
+
+            result.Add(executingAssembly);
+
+            var otherAssemblies = new[] {
+                "Grpc.Examples.Tests",
+                "Grpc.HealthCheck.Tests",
+                "Grpc.IntegrationTesting"
+            };
+            foreach (var assemblyName in otherAssemblies)
+            {
+                var location = executingAssembly.Location.Replace("Grpc.Core.Tests", assemblyName);
+                result.Add(Assembly.LoadFrom(location));
+            }
+            return result;
+        }
+    }
+}
diff --git a/src/csharp/Grpc.Core.Tests/ShutdownTest.cs b/src/csharp/Grpc.Core.Tests/ShutdownTest.cs
index a2be7ddd5e..10d666d109 100644
--- a/src/csharp/Grpc.Core.Tests/ShutdownTest.cs
+++ b/src/csharp/Grpc.Core.Tests/ShutdownTest.cs
@@ -61,17 +61,20 @@ namespace Grpc.Core.Tests
         }
 
         [Test]
-        public async Task AbandonedCall()
+        public async Task AbandonedCall_ServerKillAsync()
         {
+            var readyToShutdown = new TaskCompletionSource<object>();
             helper.DuplexStreamingHandler = new DuplexStreamingServerMethod<string, string>(async (requestStream, responseStream, context) =>
             {
+                readyToShutdown.SetResult(null);
                 await requestStream.ToListAsync();
             });
 
-            var call = Calls.AsyncDuplexStreamingCall(helper.CreateDuplexStreamingCall(new CallOptions(deadline: DateTime.UtcNow.AddMilliseconds(1))));
+            var call = Calls.AsyncDuplexStreamingCall(helper.CreateDuplexStreamingCall());
+            await readyToShutdown.Task;  // make sure handler is running
 
-            channel.ShutdownAsync().Wait();
-            server.ShutdownAsync().Wait();
+            await channel.ShutdownAsync();  // channel.ShutdownAsync() works even if there's a pending call.
+            await server.KillAsync();  // server.ShutdownAsync() would hang waiting for the call to finish.
         }
     }
 }
diff --git a/src/csharp/Grpc.Core.Tests/UserAgentStringTest.cs b/src/csharp/Grpc.Core.Tests/UserAgentStringTest.cs
new file mode 100644
index 0000000000..cc830086a6
--- /dev/null
+++ b/src/csharp/Grpc.Core.Tests/UserAgentStringTest.cs
@@ -0,0 +1,101 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Diagnostics;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Grpc.Core;
+using Grpc.Core.Internal;
+using Grpc.Core.Profiling;
+using Grpc.Core.Utils;
+using NUnit.Framework;
+
+namespace Grpc.Core.Tests
+{
+    public class UserAgentStringTest
+    {
+        const string Host = "127.0.0.1";
+
+        MockServiceHelper helper;
+        Server server;
+        Channel channel;
+
+        [TearDown]
+        public void Cleanup()
+        {
+            channel.ShutdownAsync().Wait();
+            server.ShutdownAsync().Wait();
+        }
+
+        [Test]
+        public void DefaultUserAgentString()
+        {
+            helper = new MockServiceHelper(Host);
+            server = helper.GetServer();
+            server.Start();
+            channel = helper.GetChannel();
+
+            helper.UnaryHandler = new UnaryServerMethod<string, string>((request, context) =>
+            {
+                var userAgentString = context.RequestHeaders.First(m => (m.Key == "user-agent")).Value;
+                var parts = userAgentString.Split(new [] {' '}, 2);
+                Assert.AreEqual(string.Format("grpc-csharp/{0}", VersionInfo.CurrentVersion), parts[0]);
+                Assert.IsTrue(parts[1].StartsWith("grpc-c/"));
+                return Task.FromResult("PASS");
+            });
+            Assert.AreEqual("PASS", Calls.BlockingUnaryCall(helper.CreateUnaryCall(), ""));
+        }
+
+        [Test]
+        public void ApplicationUserAgentString()
+        {
+            helper = new MockServiceHelper(Host,
+                channelOptions: new[] { new ChannelOption(ChannelOptions.PrimaryUserAgentString, "XYZ") });
+            server = helper.GetServer();
+            server.Start();
+            channel = helper.GetChannel();
+            
+            channel = helper.GetChannel();
+            helper.UnaryHandler = new UnaryServerMethod<string, string>((request, context) =>
+            {
+                var userAgentString = context.RequestHeaders.First(m => (m.Key == "user-agent")).Value;
+                var parts = userAgentString.Split(new[] { ' ' }, 3);
+                Assert.AreEqual("XYZ", parts[0]);
+                return Task.FromResult("PASS");
+            });
+            Assert.AreEqual("PASS", Calls.BlockingUnaryCall(helper.CreateUnaryCall(), ""));
+        }
+    }
+}
diff --git a/src/csharp/Grpc.Core/AsyncAuthInterceptor.cs b/src/csharp/Grpc.Core/AsyncAuthInterceptor.cs
new file mode 100644
index 0000000000..5c9ab04812
--- /dev/null
+++ b/src/csharp/Grpc.Core/AsyncAuthInterceptor.cs
@@ -0,0 +1,84 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+
+using Grpc.Core.Internal;
+using Grpc.Core.Utils;
+
+namespace Grpc.Core
+{
+    /// <summary>
+    /// Asynchronous authentication interceptor for <see cref="CallCredentials"/>.
+    /// </summary>
+    /// <param name="context">The interceptor context.</param>
+    /// <param name="metadata">Metadata to populate with entries that will be added to outgoing call's headers.</param>
+    /// <returns></returns>
+    public delegate Task AsyncAuthInterceptor(AuthInterceptorContext context, Metadata metadata);
+
+    /// <summary>
+    /// Context for an RPC being intercepted by <see cref="AsyncAuthInterceptor"/>.
+    /// </summary>
+    public class AuthInterceptorContext
+    {
+        readonly string serviceUrl;
+        readonly string methodName;
+
+        /// <summary>
+        /// Initializes a new instance of <c>AuthInterceptorContext</c>.
+        /// </summary>
+        public AuthInterceptorContext(string serviceUrl, string methodName)
+        {
+            this.serviceUrl = Preconditions.CheckNotNull(serviceUrl);
+            this.methodName = Preconditions.CheckNotNull(methodName);
+        }
+
+        /// <summary>
+        /// The fully qualified service URL for the RPC being called.
+        /// </summary>
+        public string ServiceUrl
+        {
+            get { return serviceUrl; }
+        }
+
+        /// <summary>
+        /// The method name of the RPC being called.
+        /// </summary>
+        public string MethodName
+        {
+            get { return methodName; }
+        }
+    }
+}
diff --git a/src/csharp/Grpc.Core/CallCredentials.cs b/src/csharp/Grpc.Core/CallCredentials.cs
index 5ea179dfea..a71c8904fe 100644
--- a/src/csharp/Grpc.Core/CallCredentials.cs
+++ b/src/csharp/Grpc.Core/CallCredentials.cs
@@ -41,14 +41,6 @@ using Grpc.Core.Utils;
 namespace Grpc.Core
 {
     /// <summary>
-    /// Asynchronous authentication interceptor for <see cref="CallCredentials"/>.
-    /// </summary>
-    /// <param name="authUri">URL of a service to which current remote call needs to authenticate</param>
-    /// <param name="metadata">Metadata to populate with entries that will be added to outgoing call's headers.</param>
-    /// <returns></returns>
-    public delegate Task AsyncAuthInterceptor(string authUri, Metadata metadata);
-
-    /// <summary>
     /// Client-side call credentials. Provide authorization with per-call granularity.
     /// </summary>
     public abstract class CallCredentials
diff --git a/src/csharp/Grpc.Core/CallOptions.cs b/src/csharp/Grpc.Core/CallOptions.cs
index c0f94c63c2..1fda80cb90 100644
--- a/src/csharp/Grpc.Core/CallOptions.cs
+++ b/src/csharp/Grpc.Core/CallOptions.cs
@@ -184,6 +184,7 @@ namespace Grpc.Core
                 {
                     Preconditions.CheckArgument(!newOptions.cancellationToken.CanBeCanceled,
                         "Cannot propagate cancellation token from parent call. The cancellation token has already been set to a non-default value.");
+                    newOptions.cancellationToken = propagationToken.ParentCancellationToken;
                 }
             }
                 
diff --git a/src/csharp/Grpc.Core/Channel.cs b/src/csharp/Grpc.Core/Channel.cs
index f5eec969f5..d8d43c7998 100644
--- a/src/csharp/Grpc.Core/Channel.cs
+++ b/src/csharp/Grpc.Core/Channel.cs
@@ -32,8 +32,6 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Runtime.InteropServices;
-using System.Threading;
 using System.Threading.Tasks;
 
 using Grpc.Core.Internal;
@@ -57,7 +55,7 @@ namespace Grpc.Core
         readonly string target;
         readonly GrpcEnvironment environment;
         readonly ChannelSafeHandle handle;
-        readonly List<ChannelOption> options;
+        readonly Dictionary<string, ChannelOption> options;
 
         bool shutdownRequested;
 
@@ -71,12 +69,12 @@ namespace Grpc.Core
         public Channel(string target, ChannelCredentials credentials, IEnumerable<ChannelOption> options = null)
         {
             this.target = Preconditions.CheckNotNull(target, "target");
+            this.options = CreateOptionsDictionary(options);
+            EnsureUserAgentChannelOption(this.options);
             this.environment = GrpcEnvironment.AddRef();
-            this.options = options != null ? new List<ChannelOption>(options) : new List<ChannelOption>();
 
-            EnsureUserAgentChannelOption(this.options);
             using (var nativeCredentials = credentials.ToNativeCredentials())
-            using (var nativeChannelArgs = ChannelOptions.CreateChannelArgs(this.options))
+            using (var nativeChannelArgs = ChannelOptions.CreateChannelArgs(this.options.Values))
             {
                 if (nativeCredentials != null)
                 {
@@ -173,7 +171,7 @@ namespace Grpc.Core
                 {
                     throw new OperationCanceledException("Channel has reached FatalFailure state.");
                 }
-                await WaitForStateChangedAsync(currentState, deadline);
+                await WaitForStateChangedAsync(currentState, deadline).ConfigureAwait(false);
                 currentState = handle.CheckConnectivityState(false);
             }
         }
@@ -198,7 +196,7 @@ namespace Grpc.Core
 
             handle.Dispose();
 
-            await Task.Run(() => GrpcEnvironment.Release());
+            await Task.Run(() => GrpcEnvironment.Release()).ConfigureAwait(false);
         }
 
         internal ChannelSafeHandle Handle
@@ -233,18 +231,36 @@ namespace Grpc.Core
             activeCallCounter.Decrement();
         }
 
-        private static void EnsureUserAgentChannelOption(List<ChannelOption> options)
+        private static void EnsureUserAgentChannelOption(Dictionary<string, ChannelOption> options)
         {
-            if (!options.Any((option) => option.Name == ChannelOptions.PrimaryUserAgentString))
+            var key = ChannelOptions.PrimaryUserAgentString;
+            var userAgentString = "";
+
+            ChannelOption option;
+            if (options.TryGetValue(key, out option))
             {
-                options.Add(new ChannelOption(ChannelOptions.PrimaryUserAgentString, GetUserAgentString()));
-            }
+                // user-provided userAgentString needs to be at the beginning
+                userAgentString = option.StringValue + " ";
+            };
+
+            // TODO(jtattermusch): it would be useful to also provide .NET/mono version.
+            userAgentString += string.Format("grpc-csharp/{0}", VersionInfo.CurrentVersion);
+
+            options[ChannelOptions.PrimaryUserAgentString] = new ChannelOption(key, userAgentString);
         }
 
-        private static string GetUserAgentString()
+        private static Dictionary<string, ChannelOption> CreateOptionsDictionary(IEnumerable<ChannelOption> options)
         {
-            // TODO(jtattermusch): it would be useful to also provide .NET/mono version.
-            return string.Format("grpc-csharp/{0}", VersionInfo.CurrentVersion);
+            var dict = new Dictionary<string, ChannelOption>();
+            if (options == null)
+            {
+                return dict;
+            }
+            foreach (var option in options)
+            {
+                dict.Add(option.Name, option);
+            }
+            return dict;
         }
     }
 }
diff --git a/src/csharp/Grpc.Core/ChannelOptions.cs b/src/csharp/Grpc.Core/ChannelOptions.cs
index f5ef63af54..d70673cf78 100644
--- a/src/csharp/Grpc.Core/ChannelOptions.cs
+++ b/src/csharp/Grpc.Core/ChannelOptions.cs
@@ -169,7 +169,7 @@ namespace Grpc.Core
         /// Creates native object for a collection of channel options.
         /// </summary>
         /// <returns>The native channel arguments.</returns>
-        internal static ChannelArgsSafeHandle CreateChannelArgs(List<ChannelOption> options)
+        internal static ChannelArgsSafeHandle CreateChannelArgs(ICollection<ChannelOption> options)
         {
             if (options == null || options.Count == 0)
             {
@@ -179,9 +179,9 @@ namespace Grpc.Core
             try
             {
                 nativeArgs = ChannelArgsSafeHandle.Create(options.Count);
-                for (int i = 0; i < options.Count; i++)
+                int i = 0;
+                foreach (var option in options)
                 {
-                    var option = options[i];
                     if (option.Type == ChannelOption.OptionType.Integer)
                     {
                         nativeArgs.SetInteger(i, option.Name, option.IntValue);
@@ -194,6 +194,7 @@ namespace Grpc.Core
                     {
                         throw new InvalidOperationException("Unknown option type");
                     }
+                    i++;
                 }
                 return nativeArgs;
             }
diff --git a/src/csharp/Grpc.Core/Grpc.Core.csproj b/src/csharp/Grpc.Core/Grpc.Core.csproj
index 56a06f4a9b..5b3da7c6c9 100644
--- a/src/csharp/Grpc.Core/Grpc.Core.csproj
+++ b/src/csharp/Grpc.Core/Grpc.Core.csproj
@@ -46,6 +46,7 @@
   <ItemGroup>
     <Compile Include="AsyncDuplexStreamingCall.cs" />
     <Compile Include="AsyncServerStreamingCall.cs" />
+    <Compile Include="AsyncAuthInterceptor.cs" />
     <Compile Include="CallCredentials.cs" />
     <Compile Include="IClientStreamWriter.cs" />
     <Compile Include="Internal\NativeMetadataCredentialsPlugin.cs" />
@@ -148,8 +149,8 @@
     <Error Condition="!Exists('..\packages\grpc.dependencies.openssl.redist.1.0.204.1\build\portable-net45+netcore45+wpa81+wp8\grpc.dependencies.openssl.redist.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\grpc.dependencies.openssl.redist.1.0.204.1\build\portable-net45+netcore45+wpa81+wp8\grpc.dependencies.openssl.redist.targets'))" />
     <Error Condition="!Exists('..\packages\grpc.dependencies.zlib.redist.1.2.8.10\build\portable-net45+netcore45+wpa81+wp8\grpc.dependencies.zlib.redist.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\grpc.dependencies.zlib.redist.1.2.8.10\build\portable-net45+netcore45+wpa81+wp8\grpc.dependencies.zlib.redist.targets'))" />
   </Target>
-  <ItemGroup />
-  <ItemGroup />
   <Import Project="..\packages\grpc.dependencies.openssl.redist.1.0.204.1\build\portable-net45+netcore45+wpa81+wp8\grpc.dependencies.openssl.redist.targets" Condition="Exists('..\packages\grpc.dependencies.openssl.redist.1.0.204.1\build\portable-net45+netcore45+wpa81+wp8\grpc.dependencies.openssl.redist.targets')" />
   <Import Project="..\packages\grpc.dependencies.zlib.redist.1.2.8.10\build\portable-net45+netcore45+wpa81+wp8\grpc.dependencies.zlib.redist.targets" Condition="Exists('..\packages\grpc.dependencies.zlib.redist.1.2.8.10\build\portable-net45+netcore45+wpa81+wp8\grpc.dependencies.zlib.redist.targets')" />
-</Project>
\ No newline at end of file
+  <ItemGroup />
+  <ItemGroup />
+</Project>
diff --git a/src/csharp/Grpc.Core/Internal/AsyncCallBase.cs b/src/csharp/Grpc.Core/Internal/AsyncCallBase.cs
index 953f61aa1e..92f8d77e85 100644
--- a/src/csharp/Grpc.Core/Internal/AsyncCallBase.cs
+++ b/src/csharp/Grpc.Core/Internal/AsyncCallBase.cs
@@ -238,20 +238,6 @@ namespace Grpc.Core.Internal
             }
         }
 
-        protected Exception TrySerialize(TWrite msg, out byte[] payload)
-        {
-            try
-            {
-                payload = serializer(msg);
-                return null;
-            }
-            catch (Exception e)
-            {
-                payload = null;
-                return e;
-            }
-        }
-
         protected Exception TryDeserialize(byte[] payload, out TRead msg)
         {
             using (Profilers.ForCurrentThread().NewScope("AsyncCallBase.TryDeserialize"))
diff --git a/src/csharp/Grpc.Core/Internal/ClientResponseStream.cs b/src/csharp/Grpc.Core/Internal/ClientResponseStream.cs
index b4a7335c7c..d6e34a0f04 100644
--- a/src/csharp/Grpc.Core/Internal/ClientResponseStream.cs
+++ b/src/csharp/Grpc.Core/Internal/ClientResponseStream.cs
@@ -70,12 +70,12 @@ namespace Grpc.Core.Internal
             }
             var taskSource = new AsyncCompletionTaskSource<TResponse>();
             call.StartReadMessage(taskSource.CompletionDelegate);
-            var result = await taskSource.Task;
+            var result = await taskSource.Task.ConfigureAwait(false);
             this.current = result;
 
             if (result == null)
             {
-                await call.StreamingCallFinishedTask;
+                await call.StreamingCallFinishedTask.ConfigureAwait(false);
                 return false;
             }
             return true;
diff --git a/src/csharp/Grpc.Core/Internal/NativeMetadataCredentialsPlugin.cs b/src/csharp/Grpc.Core/Internal/NativeMetadataCredentialsPlugin.cs
index 2a571cd6c9..8bb646d303 100644
--- a/src/csharp/Grpc.Core/Internal/NativeMetadataCredentialsPlugin.cs
+++ b/src/csharp/Grpc.Core/Internal/NativeMetadataCredentialsPlugin.cs
@@ -38,7 +38,7 @@ using Grpc.Core.Utils;
 
 namespace Grpc.Core.Internal
 {
-    internal delegate void NativeMetadataInterceptor(IntPtr statePtr, IntPtr serviceUrlPtr, IntPtr callbackPtr, IntPtr userDataPtr, bool isDestroy);
+    internal delegate void NativeMetadataInterceptor(IntPtr statePtr, IntPtr serviceUrlPtr, IntPtr methodNamePtr, IntPtr callbackPtr, IntPtr userDataPtr, bool isDestroy);
 
     internal class NativeMetadataCredentialsPlugin
     {
@@ -71,7 +71,7 @@ namespace Grpc.Core.Internal
             get { return credentials; }
         }
 
-        private void NativeMetadataInterceptorHandler(IntPtr statePtr, IntPtr serviceUrlPtr, IntPtr callbackPtr, IntPtr userDataPtr, bool isDestroy)
+        private void NativeMetadataInterceptorHandler(IntPtr statePtr, IntPtr serviceUrlPtr, IntPtr methodNamePtr, IntPtr callbackPtr, IntPtr userDataPtr, bool isDestroy)
         {
             if (isDestroy)
             {
@@ -81,8 +81,9 @@ namespace Grpc.Core.Internal
 
             try
             {
-                string serviceUrl = Marshal.PtrToStringAnsi(serviceUrlPtr);
-                StartGetMetadata(serviceUrl, callbackPtr, userDataPtr);
+                var context = new AuthInterceptorContext(Marshal.PtrToStringAnsi(serviceUrlPtr),
+                                                         Marshal.PtrToStringAnsi(methodNamePtr));
+                StartGetMetadata(context, callbackPtr, userDataPtr);
             }
             catch (Exception e)
             {
@@ -91,12 +92,12 @@ namespace Grpc.Core.Internal
             }
         }
 
-        private async void StartGetMetadata(string serviceUrl, IntPtr callbackPtr, IntPtr userDataPtr)
+        private async void StartGetMetadata(AuthInterceptorContext context, IntPtr callbackPtr, IntPtr userDataPtr)
         {
             try
             {
                 var metadata = new Metadata();
-                await interceptor(serviceUrl, metadata);
+                await interceptor(context, metadata).ConfigureAwait(false);
 
                 using (var metadataArray = MetadataArraySafeHandle.Create(metadata))
                 {
diff --git a/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs b/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs
index 59f4c5727c..de66759b94 100644
--- a/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs
+++ b/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs
@@ -78,13 +78,13 @@ namespace Grpc.Core.Internal
             var context = HandlerUtils.NewContext(newRpc, asyncCall.Peer, responseStream, asyncCall.CancellationToken);
             try
             {
-                Preconditions.CheckArgument(await requestStream.MoveNext());
+                Preconditions.CheckArgument(await requestStream.MoveNext().ConfigureAwait(false));
                 var request = requestStream.Current;
                 // TODO(jtattermusch): we need to read the full stream so that native callhandle gets deallocated.
-                Preconditions.CheckArgument(!await requestStream.MoveNext());
-                var result = await handler(request, context);
+                Preconditions.CheckArgument(!await requestStream.MoveNext().ConfigureAwait(false));
+                var result = await handler(request, context).ConfigureAwait(false);
                 status = context.Status;
-                await responseStream.WriteAsync(result);
+                await responseStream.WriteAsync(result).ConfigureAwait(false);
             } 
             catch (Exception e)
             {
@@ -93,13 +93,13 @@ namespace Grpc.Core.Internal
             }
             try
             {
-                await responseStream.WriteStatusAsync(status, context.ResponseTrailers);
+                await responseStream.WriteStatusAsync(status, context.ResponseTrailers).ConfigureAwait(false);
             }
             catch (OperationCanceledException)
             {
                 // Call has been already cancelled.
             }
-            await finishedTask;
+            await finishedTask.ConfigureAwait(false);
         }
     }
 
@@ -134,11 +134,11 @@ namespace Grpc.Core.Internal
             var context = HandlerUtils.NewContext(newRpc, asyncCall.Peer, responseStream, asyncCall.CancellationToken);
             try
             {
-                Preconditions.CheckArgument(await requestStream.MoveNext());
+                Preconditions.CheckArgument(await requestStream.MoveNext().ConfigureAwait(false));
                 var request = requestStream.Current;
                 // TODO(jtattermusch): we need to read the full stream so that native callhandle gets deallocated.
-                Preconditions.CheckArgument(!await requestStream.MoveNext());
-                await handler(request, responseStream, context);
+                Preconditions.CheckArgument(!await requestStream.MoveNext().ConfigureAwait(false));
+                await handler(request, responseStream, context).ConfigureAwait(false);
                 status = context.Status;
             }
             catch (Exception e)
@@ -149,13 +149,13 @@ namespace Grpc.Core.Internal
 
             try
             {
-                await responseStream.WriteStatusAsync(status, context.ResponseTrailers);
+                await responseStream.WriteStatusAsync(status, context.ResponseTrailers).ConfigureAwait(false);
             }
             catch (OperationCanceledException)
             {
                 // Call has been already cancelled.
             }
-            await finishedTask;
+            await finishedTask.ConfigureAwait(false);
         }
     }
 
@@ -190,11 +190,11 @@ namespace Grpc.Core.Internal
             var context = HandlerUtils.NewContext(newRpc, asyncCall.Peer, responseStream, asyncCall.CancellationToken);
             try
             {
-                var result = await handler(requestStream, context);
+                var result = await handler(requestStream, context).ConfigureAwait(false);
                 status = context.Status;
                 try
                 {
-                    await responseStream.WriteAsync(result);
+                    await responseStream.WriteAsync(result).ConfigureAwait(false);
                 }
                 catch (OperationCanceledException)
                 {
@@ -209,13 +209,13 @@ namespace Grpc.Core.Internal
 
             try
             {
-                await responseStream.WriteStatusAsync(status, context.ResponseTrailers);
+                await responseStream.WriteStatusAsync(status, context.ResponseTrailers).ConfigureAwait(false);
             }
             catch (OperationCanceledException)
             {
                 // Call has been already cancelled.
             }
-            await finishedTask;
+            await finishedTask.ConfigureAwait(false);
         }
     }
 
@@ -250,7 +250,7 @@ namespace Grpc.Core.Internal
             var context = HandlerUtils.NewContext(newRpc, asyncCall.Peer, responseStream, asyncCall.CancellationToken);
             try
             {
-                await handler(requestStream, responseStream, context);
+                await handler(requestStream, responseStream, context).ConfigureAwait(false);
                 status = context.Status;
             }
             catch (Exception e)
@@ -260,13 +260,13 @@ namespace Grpc.Core.Internal
             }
             try
             {
-                await responseStream.WriteStatusAsync(status, context.ResponseTrailers);
+                await responseStream.WriteStatusAsync(status, context.ResponseTrailers).ConfigureAwait(false);
             }
             catch (OperationCanceledException)
             {
                 // Call has been already cancelled.
             }
-            await finishedTask;
+            await finishedTask.ConfigureAwait(false);
         }
     }
 
@@ -284,8 +284,8 @@ namespace Grpc.Core.Internal
             var finishedTask = asyncCall.ServerSideCallAsync();
             var responseStream = new ServerResponseStream<byte[], byte[]>(asyncCall);
 
-            await responseStream.WriteStatusAsync(new Status(StatusCode.Unimplemented, "No such method."), Metadata.Empty);
-            await finishedTask;
+            await responseStream.WriteStatusAsync(new Status(StatusCode.Unimplemented, ""), Metadata.Empty).ConfigureAwait(false);
+            await finishedTask.ConfigureAwait(false);
         }
     }
 
diff --git a/src/csharp/Grpc.Core/Internal/ServerRequestStream.cs b/src/csharp/Grpc.Core/Internal/ServerRequestStream.cs
index 3fccb88abb..e7be82c318 100644
--- a/src/csharp/Grpc.Core/Internal/ServerRequestStream.cs
+++ b/src/csharp/Grpc.Core/Internal/ServerRequestStream.cs
@@ -70,7 +70,7 @@ namespace Grpc.Core.Internal
             }
             var taskSource = new AsyncCompletionTaskSource<TRequest>();
             call.StartReadMessage(taskSource.CompletionDelegate);
-            var result = await taskSource.Task;
+            var result = await taskSource.Task.ConfigureAwait(false);
             this.current = result;
             return result != null;
         }
diff --git a/src/csharp/Grpc.Core/Internal/Timespec.cs b/src/csharp/Grpc.Core/Internal/Timespec.cs
index 38fc067d9f..3031175c8a 100644
--- a/src/csharp/Grpc.Core/Internal/Timespec.cs
+++ b/src/csharp/Grpc.Core/Internal/Timespec.cs
@@ -63,20 +63,18 @@ namespace Grpc.Core.Internal
         [DllImport("grpc_csharp_ext.dll")]
         static extern int gprsharp_sizeof_timespec();
 
-        public Timespec(IntPtr tv_sec, int tv_nsec) : this(tv_sec, tv_nsec, GPRClockType.Realtime)
+        public Timespec(long tv_sec, int tv_nsec) : this(tv_sec, tv_nsec, GPRClockType.Realtime)
         {
         }
 
-        public Timespec(IntPtr tv_sec, int tv_nsec, GPRClockType clock_type)
+        public Timespec(long tv_sec, int tv_nsec, GPRClockType clock_type)
         {
             this.tv_sec = tv_sec;
             this.tv_nsec = tv_nsec;
             this.clock_type = clock_type;
         }
 
-        // NOTE: on linux 64bit  sizeof(gpr_timespec) = 16, on windows 32bit sizeof(gpr_timespec) = 8
-        // so IntPtr seems to have the right size to work on both.
-        private System.IntPtr tv_sec;
+        private long tv_sec;
         private int tv_nsec;
         private GPRClockType clock_type;
 
@@ -116,7 +114,7 @@ namespace Grpc.Core.Internal
         /// <summary>
         /// Seconds since unix epoch.
         /// </summary>
-        public IntPtr TimevalSeconds
+        public long TimevalSeconds
         {
             get
             {
@@ -176,18 +174,18 @@ namespace Grpc.Core.Internal
             {
                 // convert nanos to ticks, round up to the nearest tick
                 long ticksFromNanos = tv_nsec / NanosPerTick + ((tv_nsec % NanosPerTick != 0) ? 1 : 0);
-                long ticksTotal = checked(tv_sec.ToInt64() * TicksPerSecond + ticksFromNanos);
+                long ticksTotal = checked(tv_sec * TicksPerSecond + ticksFromNanos);
                 return UnixEpoch.AddTicks(ticksTotal);
             }
             catch (OverflowException)
             {
                 // ticks out of long range
-                return tv_sec.ToInt64() > 0 ? DateTime.MaxValue : DateTime.MinValue;
+                return tv_sec > 0 ? DateTime.MaxValue : DateTime.MinValue;
             }
             catch (ArgumentOutOfRangeException)
             {
                 // resulting date time would be larger than MaxValue
-                return tv_sec.ToInt64() > 0 ? DateTime.MaxValue : DateTime.MinValue;
+                return tv_sec > 0 ? DateTime.MaxValue : DateTime.MinValue;
             }
         }
             
@@ -226,12 +224,7 @@ namespace Grpc.Core.Internal
                     seconds--;
                     nanos += (int)NanosPerSecond;
                 }
-                // new IntPtr possibly throws OverflowException
-                return new Timespec(new IntPtr(seconds), nanos);
-            }
-            catch (OverflowException)
-            {
-                return dateTime > UnixEpoch ? Timespec.InfFuture : Timespec.InfPast;
+                return new Timespec(seconds, nanos);
             }
             catch (ArgumentOutOfRangeException)
             {
diff --git a/src/csharp/Grpc.Core/Server.cs b/src/csharp/Grpc.Core/Server.cs
index 7c94d21561..d120f95fdf 100644
--- a/src/csharp/Grpc.Core/Server.cs
+++ b/src/csharp/Grpc.Core/Server.cs
@@ -148,10 +148,10 @@ namespace Grpc.Core
             }
 
             handle.ShutdownAndNotify(HandleServerShutdown, environment);
-            await shutdownTcs.Task;
+            await shutdownTcs.Task.ConfigureAwait(false);
             DisposeHandle();
 
-            await Task.Run(() => GrpcEnvironment.Release());
+            await Task.Run(() => GrpcEnvironment.Release()).ConfigureAwait(false);
         }
 
         /// <summary>
@@ -169,8 +169,10 @@ namespace Grpc.Core
 
             handle.ShutdownAndNotify(HandleServerShutdown, environment);
             handle.CancelAllCalls();
-            await shutdownTcs.Task;
+            await shutdownTcs.Task.ConfigureAwait(false);
             DisposeHandle();
+
+            await Task.Run(() => GrpcEnvironment.Release()).ConfigureAwait(false);
         }
 
         internal void AddCallReference(object call)
@@ -268,7 +270,7 @@ namespace Grpc.Core
                 {
                     callHandler = NoSuchMethodCallHandler.Instance;
                 }
-                await callHandler.HandleCall(newRpc, environment);
+                await callHandler.HandleCall(newRpc, environment).ConfigureAwait(false);
             }
             catch (Exception e)
             {
@@ -288,7 +290,7 @@ namespace Grpc.Core
                 // after server shutdown, the callback returns with null call
                 if (!newRpc.Call.IsInvalid)
                 {
-                    Task.Run(async () => await HandleCallAsync(newRpc));
+                    Task.Run(async () => await HandleCallAsync(newRpc)).ConfigureAwait(false);
                 }
             }
 
diff --git a/src/csharp/Grpc.Core/Utils/AsyncStreamExtensions.cs b/src/csharp/Grpc.Core/Utils/AsyncStreamExtensions.cs
index cdf1e51026..02a47568e7 100644
--- a/src/csharp/Grpc.Core/Utils/AsyncStreamExtensions.cs
+++ b/src/csharp/Grpc.Core/Utils/AsyncStreamExtensions.cs
@@ -48,9 +48,9 @@ namespace Grpc.Core.Utils
         public static async Task ForEachAsync<T>(this IAsyncStreamReader<T> streamReader, Func<T, Task> asyncAction)
             where T : class
         {
-            while (await streamReader.MoveNext())
+            while (await streamReader.MoveNext().ConfigureAwait(false))
             {
-                await asyncAction(streamReader.Current);
+                await asyncAction(streamReader.Current).ConfigureAwait(false);
             }
         }
 
@@ -61,7 +61,7 @@ namespace Grpc.Core.Utils
             where T : class
         {
             var result = new List<T>();
-            while (await streamReader.MoveNext())
+            while (await streamReader.MoveNext().ConfigureAwait(false))
             {
                 result.Add(streamReader.Current);
             }
@@ -77,11 +77,11 @@ namespace Grpc.Core.Utils
         {
             foreach (var element in elements)
             {
-                await streamWriter.WriteAsync(element);
+                await streamWriter.WriteAsync(element).ConfigureAwait(false);
             }
             if (complete)
             {
-                await streamWriter.CompleteAsync();
+                await streamWriter.CompleteAsync().ConfigureAwait(false);
             }
         }
 
@@ -93,7 +93,7 @@ namespace Grpc.Core.Utils
         {
             foreach (var element in elements)
             {
-                await streamWriter.WriteAsync(element);
+                await streamWriter.WriteAsync(element).ConfigureAwait(false);
             }
         }
     }
diff --git a/src/csharp/Grpc.Examples/Grpc.Examples.csproj b/src/csharp/Grpc.Examples/Grpc.Examples.csproj
index 55462e02fd..53b2bb78c4 100644
--- a/src/csharp/Grpc.Examples/Grpc.Examples.csproj
+++ b/src/csharp/Grpc.Examples/Grpc.Examples.csproj
@@ -66,6 +66,5 @@
   </ItemGroup>
   <ItemGroup>
     <None Include="packages.config" />
-    <None Include="proto\math.proto" />
   </ItemGroup>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/src/csharp/Grpc.Examples/proto/math.proto b/src/csharp/Grpc.Examples/proto/math.proto
deleted file mode 100644
index 311e148c02..0000000000
--- a/src/csharp/Grpc.Examples/proto/math.proto
+++ /dev/null
@@ -1,80 +0,0 @@
-
-// Copyright 2015, Google Inc.
-// All rights reserved.
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-//     * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following disclaimer
-// in the documentation and/or other materials provided with the
-// distribution.
-//     * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-syntax = "proto3";
-
-package math;
-
-message DivArgs {
-  int64 dividend = 1;
-  int64 divisor = 2;
-}
-
-message DivReply {
-  int64 quotient = 1;
-  int64 remainder = 2;
-}
-
-message FibArgs {
-  int64 limit = 1;
-}
-
-message Num {
-  int64 num = 1;
-}
-
-message FibReply {
-  int64 count = 1;
-}
-
-service Math {
-  // Div divides args.dividend by args.divisor and returns the quotient and
-  // remainder.
-  rpc Div (DivArgs) returns (DivReply) {
-  }
-
-  // DivMany accepts an arbitrary number of division args from the client stream
-  // and sends back the results in the reply stream.  The stream continues until
-  // the client closes its end; the server does the same after sending all the
-  // replies.  The stream ends immediately if either end aborts.
-  rpc DivMany (stream DivArgs) returns (stream DivReply) {
-  }
-
-  // Fib generates numbers in the Fibonacci sequence.  If args.limit > 0, Fib
-  // generates up to limit numbers; otherwise it continues until the call is
-  // canceled.  Unlike Fib above, Fib has no final FibReply.
-  rpc Fib (FibArgs) returns (stream Num) {
-  }
-
-  // Sum sums a stream of numbers, returning the final result once the stream
-  // is closed.
-  rpc Sum (stream Num) returns (Num) {
-  }
-}
diff --git a/src/csharp/Grpc.HealthCheck/Grpc.HealthCheck.csproj b/src/csharp/Grpc.HealthCheck/Grpc.HealthCheck.csproj
index 8fce5d39aa..4e775a7a0c 100644
--- a/src/csharp/Grpc.HealthCheck/Grpc.HealthCheck.csproj
+++ b/src/csharp/Grpc.HealthCheck/Grpc.HealthCheck.csproj
@@ -65,7 +65,6 @@
   <ItemGroup>
     <None Include="Grpc.HealthCheck.nuspec" />
     <None Include="packages.config" />
-    <None Include="proto\health.proto" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\Grpc.Core\Grpc.Core.csproj">
@@ -81,4 +80,4 @@
   <Target Name="AfterBuild">
   </Target>
   -->
-</Project>
\ No newline at end of file
+</Project>
diff --git a/src/csharp/Grpc.HealthCheck/proto/health.proto b/src/csharp/Grpc.HealthCheck/proto/health.proto
deleted file mode 100644
index 01aa3fcf57..0000000000
--- a/src/csharp/Grpc.HealthCheck/proto/health.proto
+++ /dev/null
@@ -1,52 +0,0 @@
-// Copyright 2015, Google Inc.
-// All rights reserved.
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-//     * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following disclaimer
-// in the documentation and/or other materials provided with the
-// distribution.
-//     * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-// TODO(jtattermusch): switch to proto3 once C# supports that.
-syntax = "proto3";
-
-package grpc.health.v1alpha;
-option csharp_namespace = "Grpc.Health.V1Alpha";
-
-message HealthCheckRequest {
-  string host = 1;
-  string service = 2;
-}
-
-message HealthCheckResponse {
-  enum ServingStatus {
-    UNKNOWN = 0;
-    SERVING = 1;
-    NOT_SERVING = 2;
-  }
-  ServingStatus status = 1;
-}
-
-service Health {
-  rpc Check(HealthCheckRequest) returns (HealthCheckResponse);
-}
\ No newline at end of file
diff --git a/src/csharp/Grpc.IntegrationTesting/Grpc.IntegrationTesting.csproj b/src/csharp/Grpc.IntegrationTesting/Grpc.IntegrationTesting.csproj
index 012de45524..b0d920a34c 100644
--- a/src/csharp/Grpc.IntegrationTesting/Grpc.IntegrationTesting.csproj
+++ b/src/csharp/Grpc.IntegrationTesting/Grpc.IntegrationTesting.csproj
@@ -41,6 +41,9 @@
     <Reference Include="CommandLine">
       <HintPath>..\packages\CommandLineParser.1.9.71\lib\net45\CommandLine.dll</HintPath>
     </Reference>
+    <Reference Include="Moq">
+      <HintPath>..\packages\Moq.4.2.1510.2205\lib\net40\Moq.dll</HintPath>
+    </Reference>
     <Reference Include="nunit.framework">
       <HintPath>..\packages\NUnit.2.6.4\lib\nunit.framework.dll</HintPath>
     </Reference>
@@ -83,6 +86,7 @@
     <Compile Include="..\Grpc.Core\Version.cs">
       <Link>Version.cs</Link>
     </Compile>
+    <Compile Include="HeaderInterceptorTest.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Empty.cs" />
     <Compile Include="Messages.cs" />
diff --git a/src/csharp/Grpc.IntegrationTesting/HeaderInterceptorTest.cs b/src/csharp/Grpc.IntegrationTesting/HeaderInterceptorTest.cs
new file mode 100644
index 0000000000..1d758b7540
--- /dev/null
+++ b/src/csharp/Grpc.IntegrationTesting/HeaderInterceptorTest.cs
@@ -0,0 +1,113 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Grpc.Core;
+using Grpc.Core.Utils;
+using Grpc.Testing;
+using NUnit.Framework;
+
+namespace Grpc.IntegrationTesting
+{
+    public class HeaderInterceptorTest
+    {
+        const string Host = "localhost";
+        Server server;
+        Channel channel;
+        TestService.TestServiceClient client;
+
+        [TestFixtureSetUp]
+        public void Init()
+        {
+            server = new Server
+            {
+                Services = { TestService.BindService(new TestServiceImpl()) },
+                Ports = { { Host, ServerPort.PickUnused, ServerCredentials.Insecure } }
+            };
+            server.Start();
+
+            channel = new Channel(Host, server.Ports.Single().BoundPort, ChannelCredentials.Insecure);
+            client = TestService.NewClient(channel);
+        }
+
+        [TestFixtureTearDown]
+        public void Cleanup()
+        {
+            channel.ShutdownAsync().Wait();
+            server.ShutdownAsync().Wait();
+        }
+
+        [Test]
+        public async Task HeaderInterceptor_CreateMetadata()
+        {
+            var key = "x-grpc-test-echo-initial";
+            client.HeaderInterceptor = new HeaderInterceptor((method, metadata) =>
+            {
+                metadata.Add(key, "ABC");
+            });
+
+            var call = client.UnaryCallAsync(new SimpleRequest());
+            await call;
+
+           var responseHeaders = await call.ResponseHeadersAsync;
+           Assert.AreEqual("ABC", responseHeaders.First((entry) => entry.Key == key).Value);
+        }
+
+        [Test]
+        public async Task HeaderInterceptor_AppendMetadata()
+        {
+            var initialKey = "x-grpc-test-echo-initial";
+            var trailingKey = "x-grpc-test-echo-trailing-bin";
+
+            client.HeaderInterceptor = new HeaderInterceptor((method, metadata) =>
+            {
+                metadata.Add(initialKey, "ABC");
+            });
+
+            var headers = new Metadata
+            {
+                { trailingKey, new byte[] {0xaa} }
+            };
+            var call = client.UnaryCallAsync(new SimpleRequest(), headers: headers);
+            await call;
+
+            var responseHeaders = await call.ResponseHeadersAsync;
+            Assert.AreEqual("ABC", responseHeaders.First((entry) => entry.Key == initialKey).Value);
+            CollectionAssert.AreEqual(new byte[] {0xaa}, call.GetTrailers().First((entry) => entry.Key == trailingKey).ValueBytes);
+        }
+    }
+}
diff --git a/src/csharp/Grpc.IntegrationTesting/InteropClient.cs b/src/csharp/Grpc.IntegrationTesting/InteropClient.cs
index 5eec11abf7..b0e33e49f7 100644
--- a/src/csharp/Grpc.IntegrationTesting/InteropClient.cs
+++ b/src/csharp/Grpc.IntegrationTesting/InteropClient.cs
@@ -34,6 +34,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 using System.Text.RegularExpressions;
 using System.Threading;
 using System.Threading.Tasks;
@@ -130,8 +131,7 @@ namespace Grpc.IntegrationTesting
                 };
             }
             var channel = new Channel(options.ServerHost, options.ServerPort, credentials, channelOptions);
-            TestService.TestServiceClient client = new TestService.TestServiceClient(channel);
-            await RunTestCaseAsync(client, options);
+            await RunTestCaseAsync(channel, options);
             await channel.ShutdownAsync();
         }
 
@@ -159,8 +159,9 @@ namespace Grpc.IntegrationTesting
             return credentials;
         }
 
-        private async Task RunTestCaseAsync(TestService.TestServiceClient client, ClientOptions options)
+        private async Task RunTestCaseAsync(Channel channel, ClientOptions options)
         {
+            var client = new TestService.TestServiceClient(channel);
             switch (options.TestCase)
             {
                 case "empty_unary":
@@ -202,8 +203,14 @@ namespace Grpc.IntegrationTesting
                 case "timeout_on_sleeping_server":
                     await RunTimeoutOnSleepingServerAsync(client);
                     break;
-                case "benchmark_empty_unary":
-                    RunBenchmarkEmptyUnary(client);
+                case "custom_metadata":
+                    await RunCustomMetadataAsync(client);
+                    break;
+                case "status_code_and_message":
+                    await RunStatusCodeAndMessageAsync(client);
+                    break;
+                case "unimplemented_method":
+                    RunUnimplementedMethod(new UnimplementedService.UnimplementedServiceClient(channel));
                     break;
                 default:
                     throw new ArgumentException("Unknown test case " + options.TestCase);
@@ -227,7 +234,6 @@ namespace Grpc.IntegrationTesting
                 ResponseSize = 314159,
                 Payload = CreateZerosPayload(271828)
             };
-
             var response = client.UnaryCall(request);
 
             Assert.AreEqual(PayloadType.COMPRESSABLE, response.Payload.Type);
@@ -493,11 +499,95 @@ namespace Grpc.IntegrationTesting
             Console.WriteLine("Passed!");
         }
 
-        // This is not an official interop test, but it's useful.
-        public static void RunBenchmarkEmptyUnary(TestService.ITestServiceClient client)
+        public static async Task RunCustomMetadataAsync(TestService.ITestServiceClient client)
         {
-            BenchmarkUtil.RunBenchmark(10000, 10000,
-                                       () => { client.EmptyCall(new Empty()); });
+            Console.WriteLine("running custom_metadata");
+            {
+                // step 1: test unary call
+                var request = new SimpleRequest
+                {
+                    ResponseType = PayloadType.COMPRESSABLE,
+                    ResponseSize = 314159,
+                    Payload = CreateZerosPayload(271828)
+                };
+
+                var call = client.UnaryCallAsync(request, headers: CreateTestMetadata());
+                await call.ResponseAsync;
+
+                var responseHeaders = await call.ResponseHeadersAsync;
+                var responseTrailers = call.GetTrailers();
+
+                Assert.AreEqual("test_initial_metadata_value", responseHeaders.First((entry) => entry.Key == "x-grpc-test-echo-initial").Value);
+                CollectionAssert.AreEqual(new byte[] { 0xab, 0xab, 0xab }, responseTrailers.First((entry) => entry.Key == "x-grpc-test-echo-trailing-bin").ValueBytes);
+            }
+
+            {
+                // step 2: test full duplex call
+                var request = new StreamingOutputCallRequest
+                {
+                    ResponseType = PayloadType.COMPRESSABLE,
+                    ResponseParameters = { new ResponseParameters { Size = 31415 } },
+                    Payload = CreateZerosPayload(27182)
+                };
+
+                var call = client.FullDuplexCall(headers: CreateTestMetadata());
+                var responseHeaders = await call.ResponseHeadersAsync;
+
+                await call.RequestStream.WriteAsync(request);
+                await call.RequestStream.CompleteAsync();
+                await call.ResponseStream.ToListAsync();
+
+                var responseTrailers = call.GetTrailers();
+
+                Assert.AreEqual("test_initial_metadata_value", responseHeaders.First((entry) => entry.Key == "x-grpc-test-echo-initial").Value);
+                CollectionAssert.AreEqual(new byte[] { 0xab, 0xab, 0xab }, responseTrailers.First((entry) => entry.Key == "x-grpc-test-echo-trailing-bin").ValueBytes);
+            }
+
+            Console.WriteLine("Passed!");
+        }
+
+        public static async Task RunStatusCodeAndMessageAsync(TestService.ITestServiceClient client)
+        {
+            Console.WriteLine("running status_code_and_message");
+            var echoStatus = new EchoStatus
+            {
+                Code = 2,
+                Message = "test status message"
+            };
+
+            {
+                // step 1: test unary call
+                var request = new SimpleRequest { ResponseStatus = echoStatus };
+
+                var e = Assert.Throws<RpcException>(() => client.UnaryCall(request));
+                Assert.AreEqual(StatusCode.Unknown, e.Status.StatusCode);
+                Assert.AreEqual(echoStatus.Message, e.Status.Detail);
+            }
+
+            {
+                // step 2: test full duplex call
+                var request = new StreamingOutputCallRequest { ResponseStatus = echoStatus };
+
+                var call = client.FullDuplexCall();
+                await call.RequestStream.WriteAsync(request);
+                await call.RequestStream.CompleteAsync();
+
+                var e = Assert.Throws<RpcException>(async () => await call.ResponseStream.ToListAsync());
+                Assert.AreEqual(StatusCode.Unknown, e.Status.StatusCode);
+                Assert.AreEqual(echoStatus.Message, e.Status.Detail);
+            }
+
+            Console.WriteLine("Passed!");
+        }
+
+        public static void RunUnimplementedMethod(UnimplementedService.IUnimplementedServiceClient client)
+        {
+            Console.WriteLine("running unimplemented_method");
+            var e = Assert.Throws<RpcException>(() => client.UnimplementedCall(new Empty()));
+
+            Assert.AreEqual(StatusCode.Unimplemented, e.Status.StatusCode);
+            Assert.AreEqual("", e.Status.Detail);
+            Console.WriteLine("Passed!");
         }
 
         private static Payload CreateZerosPayload(int size)
@@ -516,5 +606,14 @@ namespace Grpc.IntegrationTesting
             Assert.IsTrue(email.Length > 0);  // spec requires nonempty client email.
             return email;
         }
+
+        private static Metadata CreateTestMetadata()
+        {
+            return new Metadata
+            {
+                {"x-grpc-test-echo-initial", "test_initial_metadata_value"},
+                {"x-grpc-test-echo-trailing-bin", new byte[] {0xab, 0xab, 0xab}}
+            };
+        }
     }
 }
diff --git a/src/csharp/Grpc.IntegrationTesting/InteropClientServerTest.cs b/src/csharp/Grpc.IntegrationTesting/InteropClientServerTest.cs
index 837ae74c45..18168f9970 100644
--- a/src/csharp/Grpc.IntegrationTesting/InteropClientServerTest.cs
+++ b/src/csharp/Grpc.IntegrationTesting/InteropClientServerTest.cs
@@ -128,9 +128,29 @@ namespace Grpc.IntegrationTesting
         }
 
         [Test]
-        public async Task TimeoutOnSleepingServerAsync()
+        public async Task TimeoutOnSleepingServer()
         {
             await InteropClient.RunTimeoutOnSleepingServerAsync(client);
         }
+
+        [Test]
+        public async Task CustomMetadata()
+        {
+            await InteropClient.RunCustomMetadataAsync(client);
+        }
+
+        [Test]
+        [Ignore("TODO: see #4427")]
+        public async Task StatusCodeAndMessage()
+        {
+            await InteropClient.RunStatusCodeAndMessageAsync(client);
+        }
+
+        [Test]
+        [Ignore("TODO: see #4427")]
+        public void UnimplementedMethod()
+        {
+            InteropClient.RunUnimplementedMethod(UnimplementedService.NewClient(channel));
+        }
     }
 }
diff --git a/src/csharp/Grpc.IntegrationTesting/MetadataCredentialsTest.cs b/src/csharp/Grpc.IntegrationTesting/MetadataCredentialsTest.cs
index 3d56678b99..1c8bfed1f6 100644
--- a/src/csharp/Grpc.IntegrationTesting/MetadataCredentialsTest.cs
+++ b/src/csharp/Grpc.IntegrationTesting/MetadataCredentialsTest.cs
@@ -40,6 +40,7 @@ using System.Threading.Tasks;
 using Grpc.Core;
 using Grpc.Core.Utils;
 using Grpc.Testing;
+using Moq;
 using NUnit.Framework;
 
 namespace Grpc.IntegrationTesting
@@ -50,37 +51,37 @@ namespace Grpc.IntegrationTesting
         Server server;
         Channel channel;
         TestService.ITestServiceClient client;
+        List<ChannelOption> options;
+        Mock<TestService.ITestService> serviceMock;
+        AsyncAuthInterceptor asyncAuthInterceptor;
 
-        [TestFixtureSetUp]
+        [SetUp]
         public void Init()
         {
-            var serverCredentials = new SslServerCredentials(new[] { new KeyCertificatePair(File.ReadAllText(TestCredentials.ServerCertChainPath), File.ReadAllText(TestCredentials.ServerPrivateKeyPath)) });
+            serviceMock = new Mock<TestService.ITestService>();
+            serviceMock.Setup(m => m.UnaryCall(It.IsAny<SimpleRequest>(), It.IsAny<ServerCallContext>()))
+                .Returns(new Func<SimpleRequest, ServerCallContext, Task<SimpleResponse>>(UnaryCallHandler));
+
             server = new Server
             {
-                Services = { TestService.BindService(new TestServiceImpl()) },
-                Ports = { { Host, ServerPort.PickUnused, serverCredentials } }
+                Services = { TestService.BindService(serviceMock.Object) },
+                Ports = { { Host, ServerPort.PickUnused, TestCredentials.CreateSslServerCredentials() } }
             };
             server.Start();
 
-            var options = new List<ChannelOption>
+            options = new List<ChannelOption>
             {
                 new ChannelOption(ChannelOptions.SslTargetNameOverride, TestCredentials.DefaultHostOverride)
             };
 
-            var asyncAuthInterceptor = new AsyncAuthInterceptor(async (authUri, metadata) =>
+            asyncAuthInterceptor = new AsyncAuthInterceptor(async (context, metadata) =>
             {
-                await Task.Delay(100);  // make sure the operation is asynchronous.
+                await Task.Delay(100).ConfigureAwait(false);  // make sure the operation is asynchronous.
                 metadata.Add("authorization", "SECRET_TOKEN");
             });
-
-            var clientCredentials = ChannelCredentials.Create(
-                new SslCredentials(File.ReadAllText(TestCredentials.ClientCertAuthorityPath)),
-                CallCredentials.FromInterceptor(asyncAuthInterceptor));
-            channel = new Channel(Host, server.Ports.Single().BoundPort, clientCredentials, options);
-            client = TestService.NewClient(channel);
         }
 
-        [TestFixtureTearDown]
+        [TearDown]
         public void Cleanup()
         {
             channel.ShutdownAsync().Wait();
@@ -90,8 +91,29 @@ namespace Grpc.IntegrationTesting
         [Test]
         public void MetadataCredentials()
         {
-            var response = client.UnaryCall(new SimpleRequest { ResponseSize = 10 });
-            Assert.AreEqual(10, response.Payload.Body.Length);
+            var channelCredentials = ChannelCredentials.Create(TestCredentials.CreateSslCredentials(),
+                CallCredentials.FromInterceptor(asyncAuthInterceptor));
+            channel = new Channel(Host, server.Ports.Single().BoundPort, channelCredentials, options);
+            client = TestService.NewClient(channel);
+
+            client.UnaryCall(new SimpleRequest {});
+        }
+
+        [Test]
+        public void MetadataCredentials_PerCall()
+        {
+            channel = new Channel(Host, server.Ports.Single().BoundPort, TestCredentials.CreateSslCredentials(), options);
+            client = TestService.NewClient(channel);
+
+            var callCredentials = CallCredentials.FromInterceptor(asyncAuthInterceptor);
+            client.UnaryCall(new SimpleRequest { }, new CallOptions(credentials: callCredentials));
+        }
+
+        private Task<SimpleResponse> UnaryCallHandler(SimpleRequest request, ServerCallContext context)
+        {
+            var authToken = context.RequestHeaders.First((entry) => entry.Key == "authorization").Value;
+            Assert.AreEqual("SECRET_TOKEN", authToken);
+            return Task.FromResult(new SimpleResponse());
         }
     }
 }
diff --git a/src/csharp/Grpc.IntegrationTesting/RunnerClientServerTest.cs b/src/csharp/Grpc.IntegrationTesting/RunnerClientServerTest.cs
index 2b51526c88..3dd91b7948 100644
--- a/src/csharp/Grpc.IntegrationTesting/RunnerClientServerTest.cs
+++ b/src/csharp/Grpc.IntegrationTesting/RunnerClientServerTest.cs
@@ -75,9 +75,10 @@ namespace Grpc.IntegrationTesting
             serverRunner.StopAsync().Wait();
         }
 
-        // Test attribute commented out to prevent running as part of the default test suite.
-        //[Test]
-        //[Category("Performance")]
+
+        [Test]
+        [Category("Performance")]
+        [Ignore("Prevent running on Jenkins")]
         public async Task ClientServerRunner()
         {
             var config = new ClientConfig
diff --git a/src/csharp/Grpc.IntegrationTesting/TestServiceImpl.cs b/src/csharp/Grpc.IntegrationTesting/TestServiceImpl.cs
index c5bfcf08c0..5a1b4cf319 100644
--- a/src/csharp/Grpc.IntegrationTesting/TestServiceImpl.cs
+++ b/src/csharp/Grpc.IntegrationTesting/TestServiceImpl.cs
@@ -33,6 +33,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using Google.Protobuf;
@@ -51,14 +52,20 @@ namespace Grpc.Testing
             return Task.FromResult(new Empty());
         }
 
-        public Task<SimpleResponse> UnaryCall(SimpleRequest request, ServerCallContext context)
+        public async Task<SimpleResponse> UnaryCall(SimpleRequest request, ServerCallContext context)
         {
+            await EnsureEchoMetadataAsync(context);
+            EnsureEchoStatus(request.ResponseStatus, context);
+
             var response = new SimpleResponse { Payload = CreateZerosPayload(request.ResponseSize) };
-            return Task.FromResult(response);
+            return response;
         }
 
         public async Task StreamingOutputCall(StreamingOutputCallRequest request, IServerStreamWriter<StreamingOutputCallResponse> responseStream, ServerCallContext context)
         {
+            await EnsureEchoMetadataAsync(context);
+            EnsureEchoStatus(request.ResponseStatus, context);
+
             foreach (var responseParam in request.ResponseParameters)
             {
                 var response = new StreamingOutputCallResponse { Payload = CreateZerosPayload(responseParam.Size) };
@@ -68,6 +75,8 @@ namespace Grpc.Testing
 
         public async Task<StreamingInputCallResponse> StreamingInputCall(IAsyncStreamReader<StreamingInputCallRequest> requestStream, ServerCallContext context)
         {
+            await EnsureEchoMetadataAsync(context);
+
             int sum = 0;
             await requestStream.ForEachAsync(async request =>
             {
@@ -78,8 +87,11 @@ namespace Grpc.Testing
 
         public async Task FullDuplexCall(IAsyncStreamReader<StreamingOutputCallRequest> requestStream, IServerStreamWriter<StreamingOutputCallResponse> responseStream, ServerCallContext context)
         {
+            await EnsureEchoMetadataAsync(context);
+
             await requestStream.ForEachAsync(async request =>
             {
+                EnsureEchoStatus(request.ResponseStatus, context);
                 foreach (var responseParam in request.ResponseParameters)
                 {
                     var response = new StreamingOutputCallResponse { Payload = CreateZerosPayload(responseParam.Size) };
@@ -97,5 +109,28 @@ namespace Grpc.Testing
         {
             return new Payload { Body = ByteString.CopyFrom(new byte[size]) };
         }
+
+        private static async Task EnsureEchoMetadataAsync(ServerCallContext context)
+        {
+            var echoInitialList = context.RequestHeaders.Where((entry) => entry.Key == "x-grpc-test-echo-initial").ToList();
+            if (echoInitialList.Any()) {
+                var entry = echoInitialList.Single();
+                await context.WriteResponseHeadersAsync(new Metadata { entry });
+            }
+
+            var echoTrailingList = context.RequestHeaders.Where((entry) => entry.Key == "x-grpc-test-echo-trailing-bin").ToList();
+            if (echoTrailingList.Any()) {
+                context.ResponseTrailers.Add(echoTrailingList.Single());
+            }
+        }
+
+        private static void EnsureEchoStatus(EchoStatus responseStatus, ServerCallContext context)
+        {
+            if (responseStatus != null)
+            {
+                var statusCode = (StatusCode)responseStatus.Code;
+                context.Status = new Status(statusCode, responseStatus.Message);
+            }
+        }
     }
 }
diff --git a/src/csharp/Grpc.IntegrationTesting/packages.config b/src/csharp/Grpc.IntegrationTesting/packages.config
index bdb3dadf44..5c59af1b7d 100644
--- a/src/csharp/Grpc.IntegrationTesting/packages.config
+++ b/src/csharp/Grpc.IntegrationTesting/packages.config
@@ -11,6 +11,7 @@
   <package id="Microsoft.Bcl.Async" version="1.0.168" targetFramework="net45" />
   <package id="Microsoft.Bcl.Build" version="1.0.21" targetFramework="net45" />
   <package id="Microsoft.Net.Http" version="2.2.29" targetFramework="net45" />
+  <package id="Moq" version="4.2.1510.2205" targetFramework="net45" />
   <package id="Newtonsoft.Json" version="7.0.1" targetFramework="net45" />
   <package id="NUnit" version="2.6.4" targetFramework="net45" />
 </packages>
\ No newline at end of file
diff --git a/src/csharp/ext/grpc_csharp_ext.c b/src/csharp/ext/grpc_csharp_ext.c
index b8705c49d3..0ef9be33a6 100644
--- a/src/csharp/ext/grpc_csharp_ext.c
+++ b/src/csharp/ext/grpc_csharp_ext.c
@@ -927,7 +927,8 @@ GPR_EXPORT void GPR_CALLTYPE grpcsharp_metadata_credentials_notify_from_plugin(
 }
 
 typedef void(GPR_CALLTYPE *grpcsharp_metadata_interceptor_func)(
-  void *state, const char *service_url, grpc_credentials_plugin_metadata_cb cb,
+  void *state, const char *service_url, const char *method_name,
+  grpc_credentials_plugin_metadata_cb cb,
   void *user_data, gpr_int32 is_destroy);
 
 static void grpcsharp_get_metadata_handler(
@@ -935,13 +936,13 @@ static void grpcsharp_get_metadata_handler(
     grpc_credentials_plugin_metadata_cb cb, void *user_data) {
   grpcsharp_metadata_interceptor_func interceptor =
       (grpcsharp_metadata_interceptor_func)(gpr_intptr)state;
-  interceptor(state, context.service_url, cb, user_data, 0);
+  interceptor(state, context.service_url, context.method_name, cb, user_data, 0);
 }
 
 static void grpcsharp_metadata_credentials_destroy_handler(void *state) {
   grpcsharp_metadata_interceptor_func interceptor =
       (grpcsharp_metadata_interceptor_func)(gpr_intptr)state;
-  interceptor(state, NULL, NULL, NULL, 1);
+  interceptor(state, NULL, NULL, NULL, NULL, 1);
 }
 
 GPR_EXPORT grpc_call_credentials *GPR_CALLTYPE grpcsharp_metadata_credentials_create_from_plugin(
diff --git a/src/csharp/generate_proto_csharp.sh b/src/csharp/generate_proto_csharp.sh
index 92348d1394..4dbd9c3308 100755
--- a/src/csharp/generate_proto_csharp.sh
+++ b/src/csharp/generate_proto_csharp.sh
@@ -30,19 +30,19 @@
 
 # Regenerates gRPC service stubs from proto files.
 set +e
-cd $(dirname $0)
+cd $(dirname $0)/../..
 
-PROTOC=../../bins/opt/protobuf/protoc
-PLUGIN=protoc-gen-grpc=../../bins/opt/grpc_csharp_plugin
-EXAMPLES_DIR=Grpc.Examples
-TESTING_DIR=Grpc.IntegrationTesting
-HEALTHCHECK_DIR=Grpc.HealthCheck
+PROTOC=bins/opt/protobuf/protoc
+PLUGIN=protoc-gen-grpc=bins/opt/grpc_csharp_plugin
+EXAMPLES_DIR=src/csharp/Grpc.Examples
+HEALTHCHECK_DIR=src/csharp/Grpc.HealthCheck
+TESTING_DIR=src/csharp/Grpc.IntegrationTesting
 
 $PROTOC --plugin=$PLUGIN --csharp_out=$EXAMPLES_DIR --grpc_out=$EXAMPLES_DIR \
-    -I $EXAMPLES_DIR/proto $EXAMPLES_DIR/proto/math.proto
-
-$PROTOC --plugin=$PLUGIN --csharp_out=$TESTING_DIR --grpc_out=$TESTING_DIR \
-    -I ../.. ../../test/proto/*.proto ../../test/proto/benchmarks/*.proto
+    -I src/proto/math src/proto/math/math.proto
 
 $PROTOC --plugin=$PLUGIN --csharp_out=$HEALTHCHECK_DIR --grpc_out=$HEALTHCHECK_DIR \
-    -I $HEALTHCHECK_DIR/proto $HEALTHCHECK_DIR/proto/health.proto
+    -I src/proto/grpc/health/v1alpha src/proto/grpc/health/v1alpha/health.proto
+
+$PROTOC --plugin=$PLUGIN --csharp_out=$TESTING_DIR --grpc_out=$TESTING_DIR \
+    -I . test/proto/{empty,messages,test}.proto test/proto/benchmarks/*.proto
diff --git a/src/csharp/tests.json b/src/csharp/tests.json
new file mode 100644
index 0000000000..4aa93668ad
--- /dev/null
+++ b/src/csharp/tests.json
@@ -0,0 +1,45 @@
+{
+  "assemblies": [
+    "Grpc.Core.Tests",
+    "Grpc.Examples.Tests",
+    "Grpc.HealthCheck.Tests",
+    "Grpc.IntegrationTesting"
+  ],
+  "tests": [
+    "Grpc.Core.Internal.Tests.AsyncCallTest",
+    "Grpc.Core.Internal.Tests.ChannelArgsSafeHandleTest",
+    "Grpc.Core.Internal.Tests.CompletionQueueEventTest",
+    "Grpc.Core.Internal.Tests.CompletionQueueSafeHandleTest",
+    "Grpc.Core.Internal.Tests.MetadataArraySafeHandleTest",
+    "Grpc.Core.Internal.Tests.TimespecTest",
+    "Grpc.Core.Tests.CallCredentialsTest",
+    "Grpc.Core.Tests.CallOptionsTest",
+    "Grpc.Core.Tests.ChannelCredentialsTest",
+    "Grpc.Core.Tests.ChannelOptionsTest",
+    "Grpc.Core.Tests.ChannelTest",
+    "Grpc.Core.Tests.ClientServerTest",
+    "Grpc.Core.Tests.CompressionTest",
+    "Grpc.Core.Tests.ContextPropagationTest",
+    "Grpc.Core.Tests.GrpcEnvironmentTest",
+    "Grpc.Core.Tests.MarshallingErrorsTest",
+    "Grpc.Core.Tests.MetadataTest",
+    "Grpc.Core.Tests.NUnitVersionTest",
+    "Grpc.Core.Tests.PerformanceTest",
+    "Grpc.Core.Tests.PInvokeTest",
+    "Grpc.Core.Tests.ResponseHeadersTest",
+    "Grpc.Core.Tests.SanityTest",
+    "Grpc.Core.Tests.ServerTest",
+    "Grpc.Core.Tests.ShutdownTest",
+    "Grpc.Core.Tests.TimeoutsTest",
+    "Grpc.Core.Tests.UserAgentStringTest",
+    "Math.Tests.MathClientServerTest",
+    "Grpc.HealthCheck.Tests.HealthClientServerTest",
+    "Grpc.HealthCheck.Tests.HealthServiceImplTest",
+    "Grpc.IntegrationTesting.HeaderInterceptorTest",
+    "Grpc.IntegrationTesting.HistogramTest",
+    "Grpc.IntegrationTesting.InteropClientServerTest",
+    "Grpc.IntegrationTesting.MetadataCredentialsTest",
+    "Grpc.IntegrationTesting.RunnerClientServerTest",
+    "Grpc.IntegrationTesting.SslCredentialsTest"
+  ]
+}
\ No newline at end of file