SharedKey that rolls back changes on failed save

[johnpatrickmorgan]

Hi! I’m starting to use swift-sharing with a custom SharedKey that interacts with a backend. It works really well but there’s one sticking point. The saving can fail, and if it does, I’d like the shared value to revert to what it was before the save was attempted. I found I could achieve this behaviour by wrapping the key, but I’m not sure if I’m overlooking a simpler solution, or if I’m trying to make the library behave in a way that’s not intended. Thanks in advance for any insight!

Example of what I mean by a wrapper:
https://gist.github.com/johnpatrickmorgan/aeee23d87645711689da06ee041a2d41#file-rollingbacksharedkey-swift