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:
var concurrentHashSet = new ConcurrentHashSet<string>( new[] { "hamster", "HAMster", "bar", }, StringComparer.OrdinalIgnoreCase); concurrentHashSet.TryRemove("foo"); if (concurrentHashSet.Contains("BAR")) { Console.WriteLine(concurrentHashSet.Count); }