dtls12_handshake_msg_start
if (!dtls12_handshake_msg_start(s->d1->hs_msg, &cbb,
int dtls12_handshake_msg_start(struct dtls12_handshake_msg *msg, CBB *body,
if (!dtls12_handshake_msg_start(hs_msg, &cbb, SSL3_MT_CLIENT_HELLO,