IO#fsync documentation typo quickfix
The documentation IO#fsync says:
"Immediately writes all buffered data in ios to disk. Note that fsync differs from using IO#sync=. The latter ensures that data is flushed from Ruby’s buffers, but doesn’t not guarantee that the underlying operating system actually writes it to disk."
I believe the "doesn't not" should be changed to "does not". Fsync(2) traditionally guarantees that the operating system writes to disk, so I'm assuming that IO#sync does not and that IO#fsync does.
There is probably a better description that could be written here, but this clears up the typo for the interim.