BIO_int_ctrl
#define BIO_set_conn_ip_family(b, f) BIO_int_ctrl(b, BIO_C_SET_CONNECT, 3, f)
#define BIO_set_accept_ip_family(b, f) BIO_int_ctrl(b, BIO_C_SET_ACCEPT, 4, f)
#define BIO_set_fd(b, fd, c) BIO_int_ctrl(b, BIO_C_SET_FD, c, fd)
#define BIO_set_read_buffer_size(b, size) BIO_int_ctrl(b, BIO_C_SET_BUFF_SIZE, size, 0)
#define BIO_set_write_buffer_size(b, size) BIO_int_ctrl(b, BIO_C_SET_BUFF_SIZE, size, 1)
long BIO_int_ctrl(BIO *bp, int cmd, long larg, int iarg);