Consider supporting filesystem lock mechanisms

Obviously concurrent changes to the same ini file are now prevented via sync.RWMutex. This in-memory lock is totally sufficient for most use cases where user needs some safety checks in the same process, but I found myself in situation where I would find an actual file-lock handy.

e.g. to prevent user from opening the file in their editor and start editing the ini file while a go program (using this library) interacts with it.

I think there may be a way to implement this in a way that it doesn't break cross-platform compatibility - just have it gracefully degrade - on systems that don't support flock.

https://golang.org/pkg/syscall/#Flock

Any thoughts - any reasons why a potential PR would not be accepted?

Seems not much resources can be found about Go flock...

• https://github.com/nightlyone/lockfile
• https://gist.github.com/jedy/4167513

Not sure how well they work cross-platform.