Based on work by Pierre-Olivier Mercier <nemunaire@nemunai.re>

closes #783

Libor Peltan authored 3 years ago and Daniel Salzman committed 3 years ago

...better matching NSEC3 presentation format

David Vasek authored 3 years ago and Daniel Salzman committed 3 years ago

By using the cumulative time since the zone expiration (instead of the last
time interval) we achieve an approximation of exponential retry backoff with
base 2 (rather than with base 3, as it was until now). Now, with every retry attempt,
the interval between refreshes only doubles (with up to 30 second jitter).

This change helps avoid excessive waiting for a refresh when a few early attempts
fail.