CommandHandler.cs

    private async Task<Game> GetCurrentState(Guid gameId) =>
        (await _repository.Load(gameId)).Aggregate(new Game(), (g, e) => Game.Apply(g, e));

    private List<IEvent> SendToAggregate(ICommand command, Game game) =>
        command switch
        {
            CreateGameCommand c => game.Handle(c),
            MakeMoveCommand c => game.Handle(c),
            _ => throw new NotImplementedException()
        };

    public async Task Handle(ICommand cmd)
    {
        Game game = await GetCurrentState(cmd.GameId);
        List<IEvent> events = SendToAggregate(cmd, game);
        await _repository.Save(cmd.GameId, events);
    }