Input
 timetm
    A tm structure that expresses a relative time. On input, tm_wday
    and tm_yday are ignored.
 tns
    Nanoseconds since time component.
 inacctm
    A tm structure that expresses seconds of inaccuracy. If tm_yday
    is negative, the inaccuracy is considered to be infinite. On
    input, tm_mday, tm_mon, tm_year, tm_wday, tm_isdst, and tm_zone
    are ignored.
 ins
    Nanoseconds of inaccuracy component.
    Output
 utc
    Resulting relative binary timestamp.