diff --git a/src/csharp/Grpc.IntegrationTesting/MetricsGrpc.cs b/src/csharp/Grpc.IntegrationTesting/MetricsGrpc.cs
index aa4f1c5..9d31d1c 100644
--- a/src/csharp/Grpc.IntegrationTesting/MetricsGrpc.cs
+++ b/src/csharp/Grpc.IntegrationTesting/MetricsGrpc.cs
@@ -112,11 +112,11 @@
       ///  Returns the values of all the gauges that are currently being maintained by
       ///  the service
       /// </summary>
-      Task GetAllGauges(global::Grpc.Testing.EmptyMessage request, IServerStreamWriter<global::Grpc.Testing.GaugeResponse> responseStream, ServerCallContext context);
+      global::System.Threading.Tasks.Task GetAllGauges(global::Grpc.Testing.EmptyMessage request, IServerStreamWriter<global::Grpc.Testing.GaugeResponse> responseStream, ServerCallContext context);
       /// <summary>
       ///  Returns the value of one gauge
       /// </summary>
-      Task<global::Grpc.Testing.GaugeResponse> GetGauge(global::Grpc.Testing.GaugeRequest request, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Grpc.Testing.GaugeResponse> GetGauge(global::Grpc.Testing.GaugeRequest request, ServerCallContext context);
     }
 
     /// <summary>Base class for server-side implementations of MetricsService</summary>
@@ -126,7 +126,7 @@
       ///  Returns the values of all the gauges that are currently being maintained by
       ///  the service
       /// </summary>
-      public virtual Task GetAllGauges(global::Grpc.Testing.EmptyMessage request, IServerStreamWriter<global::Grpc.Testing.GaugeResponse> responseStream, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task GetAllGauges(global::Grpc.Testing.EmptyMessage request, IServerStreamWriter<global::Grpc.Testing.GaugeResponse> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -134,7 +134,7 @@
       /// <summary>
       ///  Returns the value of one gauge
       /// </summary>
-      public virtual Task<global::Grpc.Testing.GaugeResponse> GetGauge(global::Grpc.Testing.GaugeRequest request, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.GaugeResponse> GetGauge(global::Grpc.Testing.GaugeRequest request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
diff --git a/src/csharp/Grpc.IntegrationTesting/ServicesGrpc.cs b/src/csharp/Grpc.IntegrationTesting/ServicesGrpc.cs
index 42bf5e0..f7071eb 100644
--- a/src/csharp/Grpc.IntegrationTesting/ServicesGrpc.cs
+++ b/src/csharp/Grpc.IntegrationTesting/ServicesGrpc.cs
@@ -111,12 +111,12 @@
       ///  One request followed by one response.
       ///  The server returns the client payload as-is.
       /// </summary>
-      Task<global::Grpc.Testing.SimpleResponse> UnaryCall(global::Grpc.Testing.SimpleRequest request, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Grpc.Testing.SimpleResponse> UnaryCall(global::Grpc.Testing.SimpleRequest request, ServerCallContext context);
       /// <summary>
       ///  One request followed by one response.
       ///  The server returns the client payload as-is.
       /// </summary>
-      Task StreamingCall(IAsyncStreamReader<global::Grpc.Testing.SimpleRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.SimpleResponse> responseStream, ServerCallContext context);
+      global::System.Threading.Tasks.Task StreamingCall(IAsyncStreamReader<global::Grpc.Testing.SimpleRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.SimpleResponse> responseStream, ServerCallContext context);
     }
 
     /// <summary>Base class for server-side implementations of BenchmarkService</summary>
@@ -126,7 +126,7 @@
       ///  One request followed by one response.
       ///  The server returns the client payload as-is.
       /// </summary>
-      public virtual Task<global::Grpc.Testing.SimpleResponse> UnaryCall(global::Grpc.Testing.SimpleRequest request, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.SimpleResponse> UnaryCall(global::Grpc.Testing.SimpleRequest request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -135,7 +135,7 @@
       ///  One request followed by one response.
       ///  The server returns the client payload as-is.
       /// </summary>
-      public virtual Task StreamingCall(IAsyncStreamReader<global::Grpc.Testing.SimpleRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.SimpleResponse> responseStream, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task StreamingCall(IAsyncStreamReader<global::Grpc.Testing.SimpleRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.SimpleResponse> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -375,7 +375,7 @@
       ///  and once the shutdown has finished, the OK status is sent to terminate
       ///  this RPC.
       /// </summary>
-      Task RunServer(IAsyncStreamReader<global::Grpc.Testing.ServerArgs> requestStream, IServerStreamWriter<global::Grpc.Testing.ServerStatus> responseStream, ServerCallContext context);
+      global::System.Threading.Tasks.Task RunServer(IAsyncStreamReader<global::Grpc.Testing.ServerArgs> requestStream, IServerStreamWriter<global::Grpc.Testing.ServerStatus> responseStream, ServerCallContext context);
       /// <summary>
       ///  Start client with specified workload.
       ///  First request sent specifies the ClientConfig followed by ClientStatus
@@ -384,15 +384,15 @@
       ///  and once the shutdown has finished, the OK status is sent to terminate
       ///  this RPC.
       /// </summary>
-      Task RunClient(IAsyncStreamReader<global::Grpc.Testing.ClientArgs> requestStream, IServerStreamWriter<global::Grpc.Testing.ClientStatus> responseStream, ServerCallContext context);
+      global::System.Threading.Tasks.Task RunClient(IAsyncStreamReader<global::Grpc.Testing.ClientArgs> requestStream, IServerStreamWriter<global::Grpc.Testing.ClientStatus> responseStream, ServerCallContext context);
       /// <summary>
       ///  Just return the core count - unary call
       /// </summary>
-      Task<global::Grpc.Testing.CoreResponse> CoreCount(global::Grpc.Testing.CoreRequest request, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Grpc.Testing.CoreResponse> CoreCount(global::Grpc.Testing.CoreRequest request, ServerCallContext context);
       /// <summary>
       ///  Quit this worker
       /// </summary>
-      Task<global::Grpc.Testing.Void> QuitWorker(global::Grpc.Testing.Void request, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Grpc.Testing.Void> QuitWorker(global::Grpc.Testing.Void request, ServerCallContext context);
     }
 
     /// <summary>Base class for server-side implementations of WorkerService</summary>
@@ -406,7 +406,7 @@
       ///  and once the shutdown has finished, the OK status is sent to terminate
       ///  this RPC.
       /// </summary>
-      public virtual Task RunServer(IAsyncStreamReader<global::Grpc.Testing.ServerArgs> requestStream, IServerStreamWriter<global::Grpc.Testing.ServerStatus> responseStream, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task RunServer(IAsyncStreamReader<global::Grpc.Testing.ServerArgs> requestStream, IServerStreamWriter<global::Grpc.Testing.ServerStatus> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -419,7 +419,7 @@
       ///  and once the shutdown has finished, the OK status is sent to terminate
       ///  this RPC.
       /// </summary>
-      public virtual Task RunClient(IAsyncStreamReader<global::Grpc.Testing.ClientArgs> requestStream, IServerStreamWriter<global::Grpc.Testing.ClientStatus> responseStream, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task RunClient(IAsyncStreamReader<global::Grpc.Testing.ClientArgs> requestStream, IServerStreamWriter<global::Grpc.Testing.ClientStatus> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -427,7 +427,7 @@
       /// <summary>
       ///  Just return the core count - unary call
       /// </summary>
-      public virtual Task<global::Grpc.Testing.CoreResponse> CoreCount(global::Grpc.Testing.CoreRequest request, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.CoreResponse> CoreCount(global::Grpc.Testing.CoreRequest request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -435,7 +435,7 @@
       /// <summary>
       ///  Quit this worker
       /// </summary>
-      public virtual Task<global::Grpc.Testing.Void> QuitWorker(global::Grpc.Testing.Void request, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.Void> QuitWorker(global::Grpc.Testing.Void request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
diff --git a/src/csharp/Grpc.IntegrationTesting/TestGrpc.cs b/src/csharp/Grpc.IntegrationTesting/TestGrpc.cs
index f1878cb..cf43a77 100644
--- a/src/csharp/Grpc.IntegrationTesting/TestGrpc.cs
+++ b/src/csharp/Grpc.IntegrationTesting/TestGrpc.cs
@@ -196,34 +196,34 @@
       /// <summary>
       ///  One empty request followed by one empty response.
       /// </summary>
-      Task<global::Grpc.Testing.Empty> EmptyCall(global::Grpc.Testing.Empty request, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Grpc.Testing.Empty> EmptyCall(global::Grpc.Testing.Empty request, ServerCallContext context);
       /// <summary>
       ///  One request followed by one response.
       /// </summary>
-      Task<global::Grpc.Testing.SimpleResponse> UnaryCall(global::Grpc.Testing.SimpleRequest request, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Grpc.Testing.SimpleResponse> UnaryCall(global::Grpc.Testing.SimpleRequest request, ServerCallContext context);
       /// <summary>
       ///  One request followed by a sequence of responses (streamed download).
       ///  The server returns the payload with client desired type and sizes.
       /// </summary>
-      Task StreamingOutputCall(global::Grpc.Testing.StreamingOutputCallRequest request, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context);
+      global::System.Threading.Tasks.Task StreamingOutputCall(global::Grpc.Testing.StreamingOutputCallRequest request, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context);
       /// <summary>
       ///  A sequence of requests followed by one response (streamed upload).
       ///  The server returns the aggregated size of client payload as the result.
       /// </summary>
-      Task<global::Grpc.Testing.StreamingInputCallResponse> StreamingInputCall(IAsyncStreamReader<global::Grpc.Testing.StreamingInputCallRequest> requestStream, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Grpc.Testing.StreamingInputCallResponse> StreamingInputCall(IAsyncStreamReader<global::Grpc.Testing.StreamingInputCallRequest> requestStream, ServerCallContext context);
       /// <summary>
       ///  A sequence of requests with each request served by the server immediately.
       ///  As one request could lead to multiple responses, this interface
       ///  demonstrates the idea of full duplexing.
       /// </summary>
-      Task FullDuplexCall(IAsyncStreamReader<global::Grpc.Testing.StreamingOutputCallRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context);
+      global::System.Threading.Tasks.Task FullDuplexCall(IAsyncStreamReader<global::Grpc.Testing.StreamingOutputCallRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context);
       /// <summary>
       ///  A sequence of requests followed by a sequence of responses.
       ///  The server buffers all the client requests and then serves them in order. A
       ///  stream of responses are returned to the client when the server starts with
       ///  first request.
       /// </summary>
-      Task HalfDuplexCall(IAsyncStreamReader<global::Grpc.Testing.StreamingOutputCallRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context);
+      global::System.Threading.Tasks.Task HalfDuplexCall(IAsyncStreamReader<global::Grpc.Testing.StreamingOutputCallRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context);
     }
 
     /// <summary>Base class for server-side implementations of TestService</summary>
@@ -232,7 +232,7 @@
       /// <summary>
       ///  One empty request followed by one empty response.
       /// </summary>
-      public virtual Task<global::Grpc.Testing.Empty> EmptyCall(global::Grpc.Testing.Empty request, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.Empty> EmptyCall(global::Grpc.Testing.Empty request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -240,7 +240,7 @@
       /// <summary>
       ///  One request followed by one response.
       /// </summary>
-      public virtual Task<global::Grpc.Testing.SimpleResponse> UnaryCall(global::Grpc.Testing.SimpleRequest request, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.SimpleResponse> UnaryCall(global::Grpc.Testing.SimpleRequest request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -249,7 +249,7 @@
       ///  One request followed by a sequence of responses (streamed download).
       ///  The server returns the payload with client desired type and sizes.
       /// </summary>
-      public virtual Task StreamingOutputCall(global::Grpc.Testing.StreamingOutputCallRequest request, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task StreamingOutputCall(global::Grpc.Testing.StreamingOutputCallRequest request, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -258,7 +258,7 @@
       ///  A sequence of requests followed by one response (streamed upload).
       ///  The server returns the aggregated size of client payload as the result.
       /// </summary>
-      public virtual Task<global::Grpc.Testing.StreamingInputCallResponse> StreamingInputCall(IAsyncStreamReader<global::Grpc.Testing.StreamingInputCallRequest> requestStream, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.StreamingInputCallResponse> StreamingInputCall(IAsyncStreamReader<global::Grpc.Testing.StreamingInputCallRequest> requestStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -268,7 +268,7 @@
       ///  As one request could lead to multiple responses, this interface
       ///  demonstrates the idea of full duplexing.
       /// </summary>
-      public virtual Task FullDuplexCall(IAsyncStreamReader<global::Grpc.Testing.StreamingOutputCallRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task FullDuplexCall(IAsyncStreamReader<global::Grpc.Testing.StreamingOutputCallRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -279,7 +279,7 @@
       ///  stream of responses are returned to the client when the server starts with
       ///  first request.
       /// </summary>
-      public virtual Task HalfDuplexCall(IAsyncStreamReader<global::Grpc.Testing.StreamingOutputCallRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task HalfDuplexCall(IAsyncStreamReader<global::Grpc.Testing.StreamingOutputCallRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -525,7 +525,7 @@
       /// <summary>
       ///  A call that no server should implement
       /// </summary>
-      Task<global::Grpc.Testing.Empty> UnimplementedCall(global::Grpc.Testing.Empty request, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Grpc.Testing.Empty> UnimplementedCall(global::Grpc.Testing.Empty request, ServerCallContext context);
     }
 
     /// <summary>Base class for server-side implementations of UnimplementedService</summary>
@@ -534,7 +534,7 @@
       /// <summary>
       ///  A call that no server should implement
       /// </summary>
-      public virtual Task<global::Grpc.Testing.Empty> UnimplementedCall(global::Grpc.Testing.Empty request, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.Empty> UnimplementedCall(global::Grpc.Testing.Empty request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -669,19 +669,19 @@
     [System.Obsolete("Service implementations should inherit from the generated abstract base class instead.")]
     public interface IReconnectService
     {
-      Task<global::Grpc.Testing.Empty> Start(global::Grpc.Testing.ReconnectParams request, ServerCallContext context);
-      Task<global::Grpc.Testing.ReconnectInfo> Stop(global::Grpc.Testing.Empty request, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Grpc.Testing.Empty> Start(global::Grpc.Testing.ReconnectParams request, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Grpc.Testing.ReconnectInfo> Stop(global::Grpc.Testing.Empty request, ServerCallContext context);
     }
 
     /// <summary>Base class for server-side implementations of ReconnectService</summary>
     public abstract class ReconnectServiceBase
     {
-      public virtual Task<global::Grpc.Testing.Empty> Start(global::Grpc.Testing.ReconnectParams request, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.Empty> Start(global::Grpc.Testing.ReconnectParams request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
 
-      public virtual Task<global::Grpc.Testing.ReconnectInfo> Stop(global::Grpc.Testing.Empty request, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.ReconnectInfo> Stop(global::Grpc.Testing.Empty request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }