This update changes the IP data saving from running on the main thread to using an async thread. This should improve performance, especially on larger servers. Note that the async data saving is only effective for the periodic data saving, so if you're one of the very few using save-interval: 0 in the config file, you might want to change it to 1.

This also fixes a rare error that could cause a delete command's changes to be lost if save-interval is 0.

And it updates the bStats metrics version to 2.2.1.