C# benchmarks: honor optimizationtarget channel arg

src/csharp/Grpc.IntegrationTesting/ClientRunners.cs

@@ -72,7 +72,7 @@ namespace Grpc.IntegrationTesting
                 Logger.Warning("ClientConfig.CoreList is not supported for C#. Ignoring the value");
             }
 
-            var channels = CreateChannels(config.ClientChannels, config.ServerTargets, config.SecurityParams);
+            var channels = CreateChannels(config.ClientChannels, config.ServerTargets, config.SecurityParams, config.ChannelArgs);
 
             return new ClientRunnerImpl(channels,
                 config.ClientType,
@@ -84,19 +84,20 @@ namespace Grpc.IntegrationTesting
                 () => GetNextProfiler());
         }
 
-        private static List<Channel> CreateChannels(int clientChannels, IEnumerable<string> serverTargets, SecurityParams securityParams)
+        private static List<Channel> CreateChannels(int clientChannels, IEnumerable<string> serverTargets, SecurityParams securityParams, IEnumerable<ChannelArg> channelArguments)
         {
             GrpcPreconditions.CheckArgument(clientChannels > 0, "clientChannels needs to be at least 1.");
             GrpcPreconditions.CheckArgument(serverTargets.Count() > 0, "at least one serverTarget needs to be specified.");
 
             var credentials = securityParams != null ? TestCredentials.CreateSslCredentials() : ChannelCredentials.Insecure;
-            List<ChannelOption> channelOptions = null;
+            var channelOptions = new List<ChannelOption>();
             if (securityParams != null && securityParams.ServerHostOverride != "")
             {
-                channelOptions = new List<ChannelOption>
-                {
-                    new ChannelOption(ChannelOptions.SslTargetNameOverride, securityParams.ServerHostOverride)
-                };
+                channelOptions.Add(new ChannelOption(ChannelOptions.SslTargetNameOverride, securityParams.ServerHostOverride));
+            }
+            foreach (var channelArgument in channelArguments)
+            {
+                channelOptions.Add(channelArgument.ToChannelOption());
             }
 
             var result = new List<Channel>();

src/csharp/Grpc.IntegrationTesting/ControlExtensions.cs

@@ -0,0 +1,43 @@
+#region Copyright notice and license
+
+// Copyright 2016 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#endregion
+
+using System;
+using Grpc.Core;
+using Grpc.Testing;
+
+namespace Grpc.IntegrationTesting
+{
+    /// <summary>
+    /// Helpers for Control.cs
+    /// </summary>
+    public static class ControlExtensions
+    {
+        public static ChannelOption ToChannelOption(this ChannelArg channelArgument)
+        {
+            switch (channelArgument.ValueCase)
+            {
+                case ChannelArg.ValueOneofCase.StrValue:
+                  return new ChannelOption(channelArgument.Name, channelArgument.StrValue);
+                case ChannelArg.ValueOneofCase.IntValue:
+                  return new ChannelOption(channelArgument.Name, channelArgument.IntValue);
+                default:
+                  throw new ArgumentException("Unsupported channel argument value.");
+            }
+        }
+    }
+}

src/csharp/Grpc.IntegrationTesting/ServerRunners.cs

@@ -78,7 +78,8 @@ namespace Grpc.IntegrationTesting
                 throw new ArgumentException("Unsupported ServerType");
             }
 
-            var server = new Server
+            var channelOptions = new List<ChannelOption>(config.ChannelArgs.Select((arg) => arg.ToChannelOption()));
+            var server = new Server(channelOptions)
             {
                 Services = { service },
                 Ports = { new ServerPort("[::]", config.Port, credentials) }