@Override
public int compareTo (Instant otherInstant)

Compares this instant to the specified instant.

The comparison is based on the time-line position of the instants. It is "consistent with equals", as defined by Comparable.

Parameters:
otherInstant    the other instant to compare to, not null

Returns:  the comparator value, negative if less, positive if greater

Exceptions:
NullPointerException    if otherInstant is null