difference method
Returns a new set with the elements of this that are not in other
.
That is, the returned set contains all the elements of this ISet that
are not elements of other
according to other.contains
.
Implementation
ISet<T> difference(Iterable<T> other) {
Set<T> otherSet = _setFromIterable(other);
return ISet._unsafeFromSet(_s.difference(otherSet), config: config);
}