A ConcurrentHashSet implementation based on .NET's ConcurrentDictionary
This implementation supports basic operations per item without HashSet's set operations as they make less sense in concurrent scenarios IMO:
varconcurrentHashSet=newConcurrentHashSet<string>(new[]{"hamster","HAMster","bar",},StringComparer.OrdinalIgnoreCase);concurrentHashSet.TryRemove("foo");if(concurrentHashSet.Contains("BAR")){Console.WriteLine(concurrentHashSet.Count);}