Retry-Afterheader, retry after value is used in preference as threshold is usually require longer wait until next request permitted.
X-Gosip-NoRetryheader is the resolution.
OnRetryhook is called after it's known that a retry is needed but before the actual retry. The mechanics of retry checks is implemented in the way that
should retry checkactually also waits for the delay. In other words,
OnRetryhook is fired right before the next retry is sent. So, if that hook is locked for a time the delay is increased correspondingly. That might be helpful for adding extra delay, yet won't work for the cases when the delays should be reduced or flatten.