diff --git a/src/csharp/Grpc.Examples/MathGrpc.cs b/src/csharp/Grpc.Examples/MathGrpc.cs
index 2d3034d28b5ff..d700a18778bb7 100644
--- a/src/csharp/Grpc.Examples/MathGrpc.cs
+++ b/src/csharp/Grpc.Examples/MathGrpc.cs
@@ -151,25 +151,25 @@ public interface IMath
       ///  Div divides args.dividend by args.divisor and returns the quotient and
       ///  remainder.
       /// </summary>
-      Task<global::Math.DivReply> Div(global::Math.DivArgs request, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Math.DivReply> Div(global::Math.DivArgs request, ServerCallContext context);
       /// <summary>
       ///  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.
       /// </summary>
-      Task DivMany(IAsyncStreamReader<global::Math.DivArgs> requestStream, IServerStreamWriter<global::Math.DivReply> responseStream, ServerCallContext context);
+      global::System.Threading.Tasks.Task DivMany(IAsyncStreamReader<global::Math.DivArgs> requestStream, IServerStreamWriter<global::Math.DivReply> responseStream, ServerCallContext context);
       /// <summary>
       ///  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.
       /// </summary>
-      Task Fib(global::Math.FibArgs request, IServerStreamWriter<global::Math.Num> responseStream, ServerCallContext context);
+      global::System.Threading.Tasks.Task Fib(global::Math.FibArgs request, IServerStreamWriter<global::Math.Num> responseStream, ServerCallContext context);
       /// <summary>
       ///  Sum sums a stream of numbers, returning the final result once the stream
       ///  is closed.
       /// </summary>
-      Task<global::Math.Num> Sum(IAsyncStreamReader<global::Math.Num> requestStream, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Math.Num> Sum(IAsyncStreamReader<global::Math.Num> requestStream, ServerCallContext context);
     }
 
     /// <summary>Base class for server-side implementations of Math</summary>
@@ -179,7 +179,7 @@ public abstract class MathBase
       ///  Div divides args.dividend by args.divisor and returns the quotient and
       ///  remainder.
       /// </summary>
-      public virtual Task<global::Math.DivReply> Div(global::Math.DivArgs request, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Math.DivReply> Div(global::Math.DivArgs request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -190,7 +190,7 @@ public abstract class MathBase
       ///  the client closes its end; the server does the same after sending all the
       ///  replies.  The stream ends immediately if either end aborts.
       /// </summary>
-      public virtual Task DivMany(IAsyncStreamReader<global::Math.DivArgs> requestStream, IServerStreamWriter<global::Math.DivReply> responseStream, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task DivMany(IAsyncStreamReader<global::Math.DivArgs> requestStream, IServerStreamWriter<global::Math.DivReply> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -200,7 +200,7 @@ public virtual Task DivMany(IAsyncStreamReader<global::Math.DivArgs> requestStre
       ///  generates up to limit numbers; otherwise it continues until the call is
       ///  canceled.  Unlike Fib above, Fib has no final FibReply.
       /// </summary>
-      public virtual Task Fib(global::Math.FibArgs request, IServerStreamWriter<global::Math.Num> responseStream, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task Fib(global::Math.FibArgs request, IServerStreamWriter<global::Math.Num> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -209,7 +209,7 @@ public virtual Task Fib(global::Math.FibArgs request, IServerStreamWriter<global
       ///  Sum sums a stream of numbers, returning the final result once the stream
       ///  is closed.
       /// </summary>
-      public virtual Task<global::Math.Num> Sum(IAsyncStreamReader<global::Math.Num> requestStream, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Math.Num> Sum(IAsyncStreamReader<global::Math.Num> requestStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
diff --git a/src/csharp/Grpc.HealthCheck/HealthGrpc.cs b/src/csharp/Grpc.HealthCheck/HealthGrpc.cs
index 967d1170bedfc..51c6a39b1d8fa 100644
--- a/src/csharp/Grpc.HealthCheck/HealthGrpc.cs
+++ b/src/csharp/Grpc.HealthCheck/HealthGrpc.cs
@@ -72,13 +72,13 @@ public interface IHealthClient
     [System.Obsolete("Service implementations should inherit from the generated abstract base class instead.")]
     public interface IHealth
     {
-      Task<global::Grpc.Health.V1.HealthCheckResponse> Check(global::Grpc.Health.V1.HealthCheckRequest request, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Grpc.Health.V1.HealthCheckResponse> Check(global::Grpc.Health.V1.HealthCheckRequest request, ServerCallContext context);
     }
 
     /// <summary>Base class for server-side implementations of Health</summary>
     public abstract class HealthBase
     {
-      public virtual Task<global::Grpc.Health.V1.HealthCheckResponse> Check(global::Grpc.Health.V1.HealthCheckRequest request, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Grpc.Health.V1.HealthCheckResponse> Check(global::Grpc.Health.V1.HealthCheckRequest request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
diff --git a/src/csharp/Grpc.IntegrationTesting/MetricsGrpc.cs b/src/csharp/Grpc.IntegrationTesting/MetricsGrpc.cs
index aa4f1c5c3ec5d..9d31d1c5146c6 100644
--- a/src/csharp/Grpc.IntegrationTesting/MetricsGrpc.cs
+++ b/src/csharp/Grpc.IntegrationTesting/MetricsGrpc.cs
@@ -112,11 +112,11 @@ public interface IMetricsService
       ///  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 @@ public abstract class MetricsServiceBase
       ///  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 @@ public virtual Task GetAllGauges(global::Grpc.Testing.EmptyMessage request, ISer
       /// <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 42bf5e0b58222..f7071ebf6bebe 100644
--- a/src/csharp/Grpc.IntegrationTesting/ServicesGrpc.cs
+++ b/src/csharp/Grpc.IntegrationTesting/ServicesGrpc.cs
@@ -111,12 +111,12 @@ public interface IBenchmarkService
       ///  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 @@ public abstract class BenchmarkServiceBase
       ///  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 @@ public abstract class BenchmarkServiceBase
       ///  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 @@ public interface IWorkerService
       ///  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 @@ public interface IWorkerService
       ///  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 @@ public abstract class WorkerServiceBase
       ///  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 @@ public virtual Task RunServer(IAsyncStreamReader<global::Grpc.Testing.ServerArgs
       ///  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 @@ public virtual Task RunClient(IAsyncStreamReader<global::Grpc.Testing.ClientArgs
       /// <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 @@ public virtual Task RunClient(IAsyncStreamReader<global::Grpc.Testing.ClientArgs
       /// <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 f1878cbb556c7..cf43a77118cf0 100644
--- a/src/csharp/Grpc.IntegrationTesting/TestGrpc.cs
+++ b/src/csharp/Grpc.IntegrationTesting/TestGrpc.cs
@@ -196,34 +196,34 @@ public interface ITestService
       /// <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 @@ public abstract class TestServiceBase
       /// <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 @@ public abstract class TestServiceBase
       /// <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 @@ public abstract class TestServiceBase
       ///  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 @@ public virtual Task StreamingOutputCall(global::Grpc.Testing.StreamingOutputCall
       ///  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 @@ public virtual Task StreamingOutputCall(global::Grpc.Testing.StreamingOutputCall
       ///  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 @@ public virtual Task FullDuplexCall(IAsyncStreamReader<global::Grpc.Testing.Strea
       ///  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 @@ public interface IUnimplementedService
       /// <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 @@ public abstract class UnimplementedServiceBase
       /// <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 @@ public interface IReconnectServiceClient
     [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, ""));
       }