cfunction
(os/mktime date-struct &opt local)
Get the broken down date-struct time expressed as the number of
seconds since January 1, 1970, the Unix epoch. Returns a real number.
Date is given in UTC unless local is truthy, in which case the date is
computed for the local timezone.
Inverse function to os/date.
(os/time) # => 1593838384
(os/date) # => {:month 6 :dst false :year-day 185 :seconds 8 :minutes 53 :week-day 6 :year 2020 :hours 4 :month-day 3}
(os/mktime (os/date)) # => 1593838390