FAILED: cloud_to_cloud:go:c++_server:unimplemented_method #15247
Description
Happens on grpc_interop_alts and grpc_interop_tocloud.
https://source.cloud.google.com/results/invocations/d0d375ad-c894-4d8e-801a-7096e0743d9d/targets/grpc%2Fcore%2Fpull_request%2Flinux%2Fgrpc_interop_alts/log
https://source.cloud.google.com/results/invocations/dd8731e1-c451-454f-8f45-3a35d48cd31c/targets/grpc%2Fcore%2Fpull_request%2Flinux%2Fgrpc_interop_tocloud/log
2018-05-01 11:05:43,367 FATAL: 2018/05/01 18:05:43 grpc.Invoke(_, _, _, _, _) = rpc error: code = Internal desc = Couldn't initialize byte buffer reader, want error code Unimplemented
exit status 1
2018-05-01 11:05:43,367 FAILED: cloud_to_cloud:go:c++_server:unimplemented_method [ret=1, pid=20437, time=1.9sec]
2018-05-01 11:18:23,087 FATAL: 2018/05/01 18:18:22 grpc.Invoke(_, _, _, _, _) = rpc error: code = Unknown desc = Exception was thrown by handler., want error code Unimplemented
exit status 1
2018-05-01 11:18:23,087 FAILED: cloud_to_cloud:go:csharp_server:unimplemented_method [ret=1, pid=27391, time=2.0sec]