Backoff: 5 s, 10 s, 20 s ... up to an hour between attempts, dead a day after the first attempt.
The failed attempts so far, the one just recorded included.
When that failure was recorded, in milliseconds.
When the next attempt is due.
Backoff: 5 s, 10 s, 20 s ... up to an hour between attempts, dead a day after the first attempt.