[ruby-core:102538] [Ruby master Feature#17363] Timeouts

Issue #17363 has been updated by naruse (Yui NARUSE).


Through my experience  on  implementing write_timeout for net/http, there are 2 layers for this type of APIs.
Low-level layer has SELECT (or wait_readable/wait_writable) and nonblock write/read APIs. (IO and Socket)
High-level layer has timeout APIs which is implemented with above. (Net::BufferedIO and Net::HTTP)

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Feature #17363: Timeouts
https://bugs.ruby-lang.org/issues/17363#change-90438

* Author: marcandre (Marc-Andre Lafortune)
* Status: Assigned
* Priority: Normal
* Assignee: ko1 (Koichi Sasada)
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Builtin methods like `Queue.pop` and `Ractor.receive` have no timeout parameter.

We should either:
- provide such a parameter
- and/or provide a `Timeout::wake` that raises an timeout error only if the block is currently sleeping.

Details:

```ruby
q = Queue.new
# ...
elem = Timeout::timeout(42) { q.pop } # => It is possible that an element is retreived from the queue but never stored in `elem`

elem = Timeout::wake(42) { q.pop } # => Guaranteed that either element is retrieved from the queue or an exception is raised, never both
Timeout::wake(42) { loop {} } # => infinite loop
# and/or
elem = q.pop(timeout: 42)
```

Currently, the only reliable way to have a Queue that accepts a timeout is to re-implement it from scratch. This post describe how involved that can be: https://spin.atomicobject.com/2017/06/28/queue-pop-with-timeout-fixed/



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