Lars Kanis 9c0582704f Fix example fiber scheduler reg. writable events
There were two issues:

1. When an IO object is waiting for writablility only (as in test_tcp_accept) the selected hash is empty.
   Therefore selected[fiber] returns nil but needs to default to 0 in order to be or'ed with IO::WRITABLE.

2. When an IO object is waiting for read- or writability (as in test_tcp_connect), but only one of these
   two events arrive, the Fiber and IO object need to be removed from the other `@readable` or `@writable` list.
2021-08-26 21:49:12 +12:00
..
2020-12-23 03:27:14 +09:00
2021-06-15 00:02:15 +09:00