For, also called "pending duration", specifies a time duration for how long the expression must
have been continuously satisfied before a check evaluation is created. When the check evaluation
is created, its "start" timestamp is set to the instant the pending duration started elapsing.
This is effectively equivalent to the "for" configuration in Prometheus alerting rules.
Default value is 0s, meaning that the check would transition immediately into one of the degraded
or critical states at the first failed evaluation.
If for is not set to 0s (or equivalent, like 0m), its value must be larger than or equal to that
of evaluationFrequency, as it does not make sense to expect the status of a check to change without another
evaluation having occurred.