You should record the event time separately [1] from the beginning/end of the measurement period - the first as a time instant in UTC ('wall clock'), the latter as a difference between two values of a guaranteed monotonically increasing clock.
This is something you need to do regardless of leap seconds to handle things like NTP kicking in to adjust your local wall clock time.
[1] - Depending on the programming environment, these might be either different timestamp types recorded separately or converted appropriately to reflect different uses, or a smart combination type like time.Time in Go.
This is something you need to do regardless of leap seconds to handle things like NTP kicking in to adjust your local wall clock time.
[1] - Depending on the programming environment, these might be either different timestamp types recorded separately or converted appropriately to reflect different uses, or a smart combination type like time.Time in Go.