private static MyStateType?MaybeUpdate(MyStateType oldState, MyUpdateType update) =>
        update.ShouldIncrement ? new MyStateType
        {
            Counter = oldState.Counter + 1
        }

                                                                                        : (MyStateType?)null;
        public StateMonitorTest(ITestOutputHelper testOutput)
        {
            _log = Logs.ToMethod(line =>
            {
                try
                {
                    testOutput.WriteLine("{0}: {1}", DateTime.Now, line);
                }
                catch { }
            }).Logger("");
            var initialState = new MyStateType {
                Counter = 0
            };

            _monitor = new StateMonitor <MyStateType, MyUpdateType>(initialState, MaybeUpdate, _log);
        }