AssetFilesKey.cs

        public class AssetFilesKey
        {
            private readonly List<string> _names;
            private readonly List<string> _sortedNames;
            public AssetFilesKey(IEnumerable<string> names)
            {
                _names = names.ToList();
                _sortedNames = _names.OrderBy(x => x).ToList();
                //_names.Sort();
            }

            public List<string> Names
            {
                get { return _names; }
            }

            public bool Equals(AssetFilesKey other)
            {
                if (ReferenceEquals(null, other)) return false;
                if (ReferenceEquals(this, other)) return true;

                if (other._names.Count != _names.Count) return false;

                return !other._sortedNames.Where((t, i) => t != _sortedNames[i]).Any();
            }

            public override bool Equals(object obj)
            {
                if (ReferenceEquals(null, obj)) return false;
                if (ReferenceEquals(this, obj)) return true;
                if (obj.GetType() != typeof (AssetFilesKey)) return false;
                return Equals((AssetFilesKey) obj);
            }

            public override int GetHashCode()
            {
                return (_names != null ? _names.Join("-").GetHashCode() : 0);
            }
        }