Ruby Hash of hash support in proto3 grpc

[Anjali Jaiswal]

I want to make a Ruby client. In my service_pb.rb file I have:

```

add_message 'request' do
  ...
  optional :test, :message, 12, 'google.protobuf.Struct'
end```

Now I am trying to pass the request params in my client.rb:

```

params = {xyz: "abc", test: { bar: "296" }}

stub = Message::Stub.new('localhost:9999', :this_channel_is_insecure)

msg = Request.new(params)

```

while running this I am getting: ArgumentError: Unknown field name 'bar' in initialization map entry.




I need to pass a Hash object in request params.