propagate statuscode from server handler

src/csharp/Grpc.Core/Internal/ServerCallHandler.cs

@@ -274,7 +274,6 @@ namespace Grpc.Core.Internal
             
             asyncCall.Initialize(newRpc.Call);
             var finishedTask = asyncCall.ServerSideCallAsync();
-            var requestStream = new ServerRequestStream<byte[], byte[]>(asyncCall);
             var responseStream = new ServerResponseStream<byte[], byte[]>(asyncCall);
 
             await responseStream.WriteStatusAsync(new Status(StatusCode.Unimplemented, "No such method."), Metadata.Empty);
@@ -286,6 +285,13 @@ namespace Grpc.Core.Internal
     {
         public static Status StatusFromException(Exception e)
         {
+            var rpcException = e as RpcException;
+            if (rpcException != null)
+            {
+                // use the status thrown by handler.
+                return rpcException.Status;
+            }
+
             // TODO(jtattermusch): what is the right status code here?
             return new Status(StatusCode.Unknown, "Exception was thrown by handler.");
         }

src/csharp/Grpc.HealthCheck.Tests/HealthClientServerTest.cs

@@ -87,9 +87,7 @@ namespace Grpc.HealthCheck.Tests
         [Test]
         public void ServiceDoesntExist()
         {
-            // TODO(jtattermusch): currently, this returns wrong status code, because we don't enable sending arbitrary status code from
-            // server handlers yet.
-            Assert.Throws(typeof(RpcException), () => client.Check(HealthCheckRequest.CreateBuilder().SetHost("").SetService("nonexistent.service").Build()));
+            Assert.Throws(Is.TypeOf(typeof(RpcException)).And.Property("Status").Property("StatusCode").EqualTo(StatusCode.NotFound), () => client.Check(HealthCheckRequest.CreateBuilder().SetHost("").SetService("nonexistent.service").Build()));
         }
 
         // TODO(jtattermusch): add test with timeout once timeouts are supported