/// <inheritdoc /> public override bool IfNotContains(T item, Action <HashSet <T> > action) => !InternalSource.Contains(item) && base.IfNotContains(item, action);
// Asumes that .Contains is a thread-safe read-only operation. // But any potentially iterative operation will be locked. /// <inheritdoc /> public override bool Contains(T item) => InternalSource.Contains(item);