gnutls_deinit(client_session);
gnutls_certificate_free_cas(client_x509_cred);
gnutls_certificate_free_keys(client_x509_cred);
gnutls_deinit(client_session);
gnutls_certificate_free_cas(client_x509_cred);
gnutls_certificate_free_keys(client_x509_cred);