os integration: fs locks

[moon-chilled]

customer:
performer:
deadline: null
estimated: null
started: null
actual: null
completed: null
confirmed: null
dependencies:

• Update intent gossip spec with proposition of implementation anoma#334

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dealing with the racy reality of mainstream oses requires fs locks. there's a tracking issue for adding them to erlang; they will hopefully be in the next release? in the mean time we can either punt or nif it