Module atomic 

Atomic file writes.

Plain fs::write truncates the target to zero length and then writes the new contents in place. A crash / kill / disk-full between those two steps leaves the file empty or half-written — catastrophic for session, checkpoint, and plugin-lockfile state that is rewritten in full on every save. write_atomic writes to a temp sibling, fsyncs it, then renames over the target, so a reader always sees either the old complete file or the new complete file.

Functions

write_atomic

Write bytes to path atomically: temp file in the same directory → sync_all → rename over the destination. The rename is atomic on the same filesystem (and replaces an existing target on both Unix and Windows).