public record CreateUserCommand(string Name, string Email) : INexCommand<UserDto>;

public class CreateUserHandler : INexRequestHandler<CreateUserCommand, UserDto>
{
    public Task<UserDto> Handle(CreateUserCommand request, CancellationToken ct)
    {
        var user = new UserDto(Guid.NewGuid(), request.Name, request.Email);
        return Task.FromResult(user);
    }
}

// Usage
var result = await nexMediator.Send(new CreateUserCommand("Jane", "[email protected]"));

public record GetUserQuery(Guid Id) : INexQuery<UserDto>;

public class GetUserHandler : INexRequestHandler<GetUserQuery, UserDto>
{
    public Task<UserDto> Handle(GetUserQuery query, CancellationToken ct)
    {
        return Task.FromResult(new UserDto(query.Id, "Jane Doe", "[email protected]"));
    }
}

// Usage
var result = await nexMediator.Send(new GetUserQuery(Guid.Parse("...")));

public record SendEmailToUserNotification(string Email, string Subject, string Message) : INexNotification;

public class EmailSender : INexNotificationHandler<SendEmailToUserNotification>
{
    public Task Handle(SendEmailToUserNotification notification, CancellationToken ct)
    {
        Console.WriteLine($"Sending email to {notification.Email} with subject {notification.Subject}");
        return Task.CompletedTask;
    }
}

// Usage
await nexMediator.Publish(new SendEmailToUserNotification("[email protected]", "Welcome", "Thanks for joining!"));

public record StreamUsersRequest() : INexStreamRequest<UserDto>;

public class StreamUsersHandler : INexStreamRequestHandler<StreamUsersRequest, UserDto>
{
    public async IAsyncEnumerable<UserDto> Handle(StreamUsersRequest request, [EnumeratorCancellation] CancellationToken ct)
    {
        var users = new[]
        {
            new UserDto(Guid.NewGuid(), "Jane", "[email protected]"),
            new UserDto(Guid.NewGuid(), "John", "[email protected]")
        };

        foreach (var user in users)
        {
            yield return user;
            await Task.Delay(100, ct); // simulate stream delay
        }
    }
}

// Usage
await foreach (var user in nexMediator.Stream(new StreamUsersRequest(), cancellationToken))
{
    Console.WriteLine(user.Name);
}

return Result<UserDto>.Success(data);
return Result<UserDto>.BadRequest("Email is invalid");
return Result<UserDto>.NotFound("User not found");