SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(ctx));
SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb);
SSL_CTX_set_tlsext_servername_arg(server_sni, state);
SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(ctx));
SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb);
SSL_CTX_set_tlsext_servername_arg(server_sni, state);