public async Task AppendToEmptyStream()
        {
            var appender = new MemoryAppendStoreAsync();
            var es = new EventStoreAsync(appender);
            
            var dispatcher = new TastyDomainDriven.Sample.CommandServices.SaySomething(es);

            await
                dispatcher.GetExecutor(new SayCommand()
                {
                    PersonId = new PersonId(1),
                    Say = "I have something to say",
                    Timestamp = DateTime.UtcNow
                }).Execute();

            Assert.Equal(1, (await es.ReplayAll()).Events.Count);
        }
        public async Task AppendToEmptyStream()
        {
            var appender = new MemoryAppendStoreAsync();
            var es       = new EventStoreAsync(appender);

            var dispatcher = new TastyDomainDriven.Sample.CommandServices.SaySomething(es);

            await
            dispatcher.GetExecutor(new SayCommand()
            {
                PersonId  = new PersonId(1),
                Say       = "I have something to say",
                Timestamp = DateTime.UtcNow
            }).Execute();

            Assert.Equal(1, (await es.ReplayAll()).Events.Count);
        }