public async Task Apply(TestAggregateCreated @event)
        {
            await Task.Yield();

            ACount += GetCharCount('a', @event.Name);
            ECount += GetCharCount('e', @event.Name);
            ICount += GetCharCount('i', @event.Name);
            OCount += GetCharCount('o', @event.Name);
            UCount += GetCharCount('u', @event.Name);
        }
        public Task <TestState> Apply(TestAggregateCreated @event)
        {
            Console.Write("C");
            // Console.Write(Environment.CurrentManagedThreadId);
            // Console.Write("|" + Environment.CurrentManagedThreadId);

            var s = new TestState(this)
            {
                StreamName = @event.Id,
                Name       = @event.Name
            };

            return(Task.FromResult(s));
        }