A delivery and the five-minute reconcile were two paths that applied, ordered only by a lock, and
each order it allowed was met live (issues 257, 261, 267). Now both only enqueue: one worker takes
the newest declaration held when it starts, applies it once and makes one report, and reports leave
in the order they are made.
A declaration may carry the controller's lease epoch beside its sequence; one older than what this
node applied is refused before anything is touched, counted, logged and reported. A report carries
the declaration's epoch and sequence and the host's own report sequence, kept on disk so it goes on
increasing across restarts and self-updates. Without an epoch, today's behaviour stands.
A host that delivered its own successor stood aside before the report of
that apply was published, so it failed with 'context canceled' and the
release plan waited for a report that never came (novox/hq issue 264).
Reports are now published on a context the stand-aside does not cancel,
and the last apply's report is kept until the broker takes it and said
again on the next link, so a crash between apply and report is covered too.
jochen