var actions = new List<Action>();

for (int i = 0; i < 5; i++)
{
    actions.Add(() => Console.WriteLine(i));
}

foreach (var action in actions)
{
    action();
}

0
1
2
3
4

5
5
5
5
5

for (int i = 0; i < 5; i++)
{
    int copy = i;
    actions.Add(() => Console.WriteLine(copy));
}

public class Program
{
    public static void Main()
    {
        var obj = new Counter();
        for (int i = 0; i < 3; i++)
        {
            Console.WriteLine(obj++);
        }
    }
}

public class Counter
{
    private int _value = 0;

    public static Counter operator ++(Counter c)
    {
        c._value++;
        return c;
    }

    public static implicit operator int(Counter c)
    {
        return c._value;
    }
}

var template = File.ReadAllText("Templates/InvoiceTemplate.html");
var compiled = Handlebars.Compile(template);
string html = compiled(data);

// Скачать Chromium
var fetcher = new BrowserFetcher();
await fetcher.DownloadAsync();

// Рендер в PDF
using var browser = await Puppeteer.LaunchAsync(new LaunchOptions { Headless = true });
using var page = await browser.NewPageAsync();
await page.SetContentAsync(html);
byte[] pdf = await page.PdfDataAsync(new PdfOptions {
    Format = PaperFormat.A4,
    PrintBackground = true,
    MarginOptions = new MarginOptions { Top = "50px", Right = "20px", Bottom = "50px", Left = "20px" }
});