secondsSinceEpoch property
int
secondsSinceEpoch
Number of seconds since epoch time
The Unix epoch (or Unix time or POSIX time or Unix timestamp) is the number of seconds that have elapsed since January 1, 1970 (midnight UTC/GMT), not counting leap seconds (in ISO 8601: 1970-01-01T00:00:00Z). Literally speaking the epoch is Unix time 0 (midnight 1/1/1970).
Implementation
int get secondsSinceEpoch => millisecondsSinceEpoch ~/ 1000;