Enum CompactOutcome 

enum CompactOutcome {
    NotRenamed(Error),
    Renamed(Result<(JournalFile, bool)>),
}

Result of Writer::compact’s blocking work, distinguishing whether the rename that makes the new file live was reached: that is the point past which the writer’s old handle is stale and must be replaced (or, on failure to do so, discarded) rather than reused.

Variants

NotRenamed(Error)

The temp file was never renamed over the journal; the writer’s existing handle is untouched and still valid.

Renamed(Result<(JournalFile, bool)>)

The rename succeeded; the writer needs the freshly opened file (and its header-written state) to replace its now-stale handle.