*
* @finish will be called when an I/O operation fails, or you call
* io_close() on the connection. errno will be set to the value
- * after the failed I/O, or at the call to io_close().
+ * after the failed I/O, or at the call to io_close(). The fd
+ * will be closed (unless a duplex) before @finish is called.
*
* Example:
* static void finish(struct io_conn *conn, void *unused)