BIO_C_GET_WRITE_BUF_SIZE
case BIO_C_GET_WRITE_BUF_SIZE:
case BIO_C_GET_WRITE_BUF_SIZE: /* Non-threadsafe */
#define BIO_get_write_buf_size(b, size) (size_t)BIO_ctrl(b, BIO_C_GET_WRITE_BUF_SIZE, size, NULL)
