Hi,
I find marking protobuf field as 'required' sometimes causing trouble: serializing a message without filling up required field generates errors and this is hard to change due to backwards compatibility. And this message type is actually discouraged by protobuf: https://developers.google.com/protocol-buffers/docs/proto#specifying-field-rules So is there a particular reason we are doing it? I would suggest to use optional and repeated onwards if possible and add more verification logic instead. /Jay
