instance of filled OpenFileStats
Note: In order to get the number of open files, this method iterates through the directory entires in /proc VFS. This implies that it should not be called multiple times a second, as there might be performance implications. Ideally, it's called every 30 seconds, or so, just to generate the stats.log as needed.
ErrnoException if the underlying system calls fail.
Gets the file descriptor stats for the process.