Add returns the time t+d.

AddMicros adds the microsecond delta to the provided time value.

Decode reverses the three integers returned from Encode and produces an equal Duration to the original.

DiffMicros computes the microsecond difference between two time values.

ErrEncodeOverflow is returned by Encode when the sortNanos returned would have overflowed or underflowed.

A Duration represents a length of time.