remove method
Returns a new set containing the current set minus the given item. However, if the given item didn't exist in the current set, it will return the current set (same instance).
Implementation
ISet<T> remove(T item) {
final S<T> result = _s.remove(item);
return identical(result, _s)
? this
: ISet<T>._unsafe(
result,
config: config,
);
}