tlsext_client_build
if (!tlsext_client_build(s, SSL_TLSEXT_MSG_CH, &client_hello)) {
int tlsext_client_build(SSL *s, uint16_t msg_type, CBB *cbb);
if (!tlsext_client_build(s, SSL_TLSEXT_MSG_CH, cbb))
if (!tls13_cert_add(ctx, &cert_list, cpk->x509, tlsext_client_build))
if (!tls13_cert_add(ctx, &cert_list, cert, tlsext_client_build))
if (!tlsext_client_build(ssl, SSL_TLSEXT_MSG_CH, &cbb)) {
if (!tlsext_client_build(ssl, SSL_TLSEXT_MSG_CH, &cbb)) {