local returnState TIME_CURRENT TIME_NEXT_HOUR SECONDS_UNTIL_NEXT_HOUR
TIME_CURRENT="$(date --iso-8601=seconds)"; # Produce `date`-parsable current timestamp with resolution of 1 second.
TIME_NEXT_HOUR="$(date -d "$TIME_CURRENT next hour" --iso-8601=hours)"; # Produce `date`-parsable current time stamp with resolution of 1 second.
local returnState TIME_CURRENT TIME_NEXT_HOUR SECONDS_UNTIL_NEXT_HOUR
TIME_CURRENT="$(date --iso-8601=seconds)"; # Produce `date`-parsable current timestamp with resolution of 1 second.
TIME_NEXT_HOUR="$(date -d "$TIME_CURRENT next hour" --iso-8601=hours)"; # Produce `date`-parsable current time stamp with resolution of 1 second.