[okanesen]

You can use fsync() [0] for that.

[0]: https://itunes.apple.com/us/app/fsync/id964427882?mt=8

[QasimK]

Thank you! So as it is available on iOS, I need to adjust my comment to reflect what I mean. There isn’t a free, open-source, community-driven implementation for iOS, keeping with the nature of the project.