distinct method
Returns a new iterable with duplicates removed, preserving nulls.
Example:
Iterable<int?>? numbers = [1, 2, 2, 3, null, null];
final distinct = numbers.distinct();
print(distinct); // Output: [1, 2, 3, null]
Implementation
Iterable<T?> distinct() =>
this == null ? Iterable.empty() : validate().toSet();