io/wait should have a way to avoid FIONREAD
I would like an API method for io/wait which bypasses FIONREAD. Some IO
objects I work with (e.g. Linux eventfd) to not support FIONREAD.
I can implement any proposed API for io/wait, but I don't know what it should
be. Perhaps just "IO#wait_readable", since I also have
http://redmine.ruby-lang.org/issues/4646 open for IO#wait_writable.
Meanwhile, I will use IO.select. I believe IO#wait_* will be a better
API that is easier-to-use and potentially faster (it can bypass array
scanning and use poll() for high FDs in Linux).