[mbed-tls] DTLS Mutual authentication

Dear,

I would like to have mutual authentication using dtls_client.c and dtls_server.c examples. In the current version of the example, the client does not send his own certificate and the server does not verify the certificate of the client. Could you please provide me the changes that I need to make in both dtls_client.c and dtls_server.c examples?

Best regards, Farhad