EnumSpeed_06

 static class EnumDefinitionTests
    {
        const int _iterationsNo = 100000;
        static InvoicePaymentMethod[] _enumsToBeChecked;
        static EnumDefinitionTests()
        {
            _enumsToBeChecked = new InvoicePaymentMethod[_iterationsNo];
            Random random = new Random();
            for(int i=0; i< _iterationsNo; i++)
            {
                var randomNumber = random.Next(65, 100);
                var enumToAdd = randomNumber > 96 ? InvoicePaymentMethod.Undefined : (InvoicePaymentMethod)randomNumber;
                _enumsToBeChecked[i] = enumToAdd;
            }
        }

        public static void Test()
        {
            Console.WriteLine("With Enum.IsDefined method:");

            Clock.BenchmarkTime((j) =>
            {
                _enumsToBeChecked[j].IsUndefined_WithEnumIsDefined();
            }, _iterationsNo);

            Console.WriteLine("=======================");
            Console.WriteLine("Comparing all values directly:");

            Clock.BenchmarkTime((j) =>
            {
                _enumsToBeChecked[j].IsUndefined_WithComparingAllValidValuesDirectly();
            }, _iterationsNo);

            Console.WriteLine("=======================");
            Console.WriteLine("With HashSet:");

            Clock.BenchmarkTime((j) =>
            {
                _enumsToBeChecked[j].IsUndefined_WithHashSet();
            }, _iterationsNo);

            Console.WriteLine("=======================");
            Console.ReadKey();
        }
    }