e.g. persist for one day in the winter and 4 days in summer.
[x] time restrictions (start and/or end day of year)
[x] the ability to specify multiple config sets in a single config file, for different times of year. e.g. setting days_to_persist to 2 for part of the year and to 4 for another part of the year
e.g. persist for one day in the winter and 4 days in summer.
days_to_persistto 2 for part of the year and to 4 for another part of the year