head_onwire_len
buf = alloc_conn_buf(con, head_onwire_len(ctrl_len, false));
buf = alloc_conn_buf(con, head_onwire_len(ctrl_len, false));
buf = alloc_conn_buf(con, head_onwire_len(ctrl_len, false));
buf = alloc_conn_buf(con, head_onwire_len(SHA256_DIGEST_SIZE,
buf = alloc_conn_buf(con, head_onwire_len(ctrl_len, con_secure(con)));
buf = alloc_conn_buf(con, head_onwire_len(ctrl_len, con_secure(con)));
head_len = head_onwire_len(ctrl_len, false);