Thanks for your reply.
In `GRPC_SSL_DONT_REQUEST_CLIENT_CERTIFICATE` mode, The client needs to
verify the server, and the server needs to send the server certificate to
the client. These processes should also be under the TLS protocol, but
through the packet capture, there is no TLS.
Note that you are using `GRPC_SSL_DONT_REQUEST_CLIENT_CERTIFICATE`. In that
mode, the server does not request (nor require) client certificates.
If you want the server to require client certificates, you could use
`GRPC_SSL_REQUEST_AND_REQUIRE_CLIENT_CERTIFICATE_AND_VERIFY` instead of
