pub const SLOW_DOWN_INCREMENT: Duration;Expand description
The minimum a slow_down lengthens the poll interval by.
RFC 8628 §3.5: on slow_down “the interval MUST be increased by 5 seconds
for this and all subsequent requests”. GitHub also returns the new interval
in the response body; DeviceFlow::poll_once takes whichever is larger, so
the RFC’s floor holds even against a response that omits or under-states it.