var id = Guid.CreateVersion7();           // ✅ UUIDv7
var now = DateTimeOffset.UtcNow;          // ✅ UTC timestamp

public record BookAdded(Guid Id, string Title, decimal Price);

public record AddBookCommand(string Title, decimal Price);

public void Apply(BookAdded @event)
{
    Id = @event.Id;
    Title = @event.Title;
}

public static class AddBookHandler
{
    public static BookAdded Handle(AddBookCommand cmd) =>
        new(Guid.CreateVersion7(), cmd.Title, cmd.Price);
}

var result = await cache.GetOrCreateAsync(
    $"books:{culture}",
    async ct => await session.Query<BookProjection>().ToListAsync(ct),
    tags: [CacheTags.BookList],
    cancellationToken: ct);

await cache.RemoveByTagAsync(CacheTags.BookList, ct);

public record BookUpdatedNotification(Guid Id) : IDomainEventNotification;

[Test]
public async Task Should_Create_Book()
{
    var result = await client.CreateBookAsync(request);
    await Assert.That(result.Id).IsNotNull();
}

namespace BookStore.ApiService.Handlers;  // ✅ File-scoped