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diff --git a/src/csharp/Grpc.HealthCheck/HealthServiceImpl.cs b/src/csharp/Grpc.HealthCheck/HealthServiceImpl.cs
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+#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.Text;
+using System.Threading.Tasks;
+
+using Grpc.Core;
+using Grpc.Core.Utils;
+using Grpc.Health.V1Alpha;
+
+namespace Grpc.HealthCheck
+{
+    /// <summary>
+    /// Implementation of a simple Health service. Useful for health checking.
+    /// 
+    /// Registering service with a server:
+    /// <code>
+    /// var serviceImpl = new HealthServiceImpl();
+    /// server = new Server();
+    /// server.AddServiceDefinition(Grpc.Health.V1Alpha.Health.BindService(serviceImpl));
+    /// </code>
+    /// </summary>
+    public class HealthServiceImpl : Grpc.Health.V1Alpha.Health.IHealth
+    {
+        private readonly object myLock = new object();
+        private readonly Dictionary<Key, HealthCheckResponse.Types.ServingStatus> statusMap = 
+            new Dictionary<Key, HealthCheckResponse.Types.ServingStatus>();
+
+        /// <summary>
+        /// Sets the health status for given host and service.
+        /// </summary>
+        /// <param name="host">The host. Cannot be null.</param>
+        /// <param name="service">The service. Cannot be null.</param>
+        /// <param name="status">the health status</param>
+        public void SetStatus(string host, string service, HealthCheckResponse.Types.ServingStatus status)
+        {
+            lock (myLock)
+            {
+                statusMap[CreateKey(host, service)] = status;
+            }
+        }
+
+        /// <summary>
+        /// Clears health status for given host and service.
+        /// </summary>
+        /// <param name="host">The host. Cannot be null.</param>
+        /// <param name="service">The service. Cannot be null.</param>
+        public void ClearStatus(string host, string service)
+        {
+            lock (myLock)
+            {
+                statusMap.Remove(CreateKey(host, service));
+            }
+        }
+        
+        /// <summary>
+        /// Clears statuses for all hosts and services.
+        /// </summary>
+        public void ClearAll()
+        {
+            lock (myLock)
+            {
+                statusMap.Clear();
+            }
+        }
+
+        public Task<HealthCheckResponse> Check(ServerCallContext context, HealthCheckRequest request)
+        {
+            lock (myLock)
+            {
+                var host = request.HasHost ? request.Host : "";
+                var service = request.HasService ? request.Service : "";
+
+                HealthCheckResponse.Types.ServingStatus status;
+                if (!statusMap.TryGetValue(CreateKey(host, service), out status))
+                {
+                    // TODO(jtattermusch): returning specific status from server handler is not supported yet.
+                    throw new RpcException(new Status(StatusCode.NotFound, ""));
+                }
+                return Task.FromResult(HealthCheckResponse.CreateBuilder().SetStatus(status).Build());
+            }
+        }
+
+        private static Key CreateKey(string host, string service)
+        {
+            return new Key(host, service);
+        }
+
+        private struct Key
+        {
+            public Key(string host, string service)
+            {
+                this.Host = Preconditions.CheckNotNull(host);
+                this.Service = Preconditions.CheckNotNull(service);
+            }
+
+            readonly string Host;
+            readonly string Service;
+        }
+    }
+}