“Every file is only ever written to from a single client, and will be asynchronously made available to all other clients, and after some period of time has elapsed you can safely switch to always writing to the file from a different client”.
Yep. See e.g. steam cloud saves, which is literally just Dropbox for your video game save files. Bidi sync is a super common pattern if you look for it, I'm surprised at all the hate it's getting here.
“Every file is only ever written to from a single client, and will be asynchronously made available to all other clients, and after some period of time has elapsed you can safely switch to always writing to the file from a different client”.